Takes no input and returns the size as a u64. Needed by Katamari Damacy Reroll to boot.

Based off RE, the backing code only ever seems to use 0-2 as the range
of values 1 being a generic log enable, with 2 indicating logging should
go to the SD card. These are used as a set of flags internally.

Given we only care about receiving the log in general, we can just
always signify that we want logging in general.

We can just return a new instance of this when it's requested. This only
ever holds pointers to the existing registed caches, so it's not a large
object. Plus, this also gets rid of the need to keep around a separate
member function just to properly clear out the union.

Gets rid of one of five globals in the filesystem code.

This is the same behavior-wise as DeleteDirectoryRecursively, with the
only difference being that it doesn't delete the top level directory in
the hierarchy, so given:

root_dir/
  - some_dir/
    - File.txt
  - OtherFile.txt

The end result is just:

root_dir/

Changed logging to be "Log before execution", Added more error logging, all services should now log on some level

Keeps filesystem-related error codes in one spot.

Prevents unnecessary re-reads of the metadata and unnecessary temporary objects.

Returns the raw NACP bytes and the raw icon bytes into a title-provided buffer. Pulls from Registration Cache for control data, returning all zeros should it not exist.

Equates to yuzu_dir/dump/<title id>/

An object to read SaveDataInfo objects, which describe a unique save on the system. This implementation iterates through all the directories in the save data space and uses the paths to reconstruct the metadata.

Needed by Checkpoint. Returns an object that can iterate through all savedata on the system.

file_sys/registered_cache: Use unique_ptr and regular pointers instead of shared_ptrs where applicable

The data retrieved in these cases are ultimately chiefly owned by either
the RegisteredCache instance itself, or the filesystem factories. Both
these should live throughout the use of their contained data. If they
don't, it should be considered an interface/design issue, and using
shared_ptr instances here would mask that, as the data would always be
prolonged after the main owner's lifetime ended.

This makes the lifetime of the data explicit and makes it harder to
accidentally create cyclic references. It also makes the interface
slightly more flexible than the previous API, as a shared_ptr can be
created from a unique_ptr, but not the other way around, so this allows
for that use-case if it ever becomes necessary in some form.

filesystem: Make CreateFactories() and InstallInterface() take a VfsFilesystem instance by reference

Neither of these functions alter the ownership of the provided pointer,
so we can simply make the parameters a reference rather than a direct
shared pointer alias. This way we also disallow passing incorrect memory values like
nullptr.

Adds new functions that have been given names to the table. Information
is based off what is provided on Switchbrew.

With these, `Nintendo Entertainment System - Nintendo Switch Online` loads

When a destructor isn't defaulted into a cpp file, it can cause the use
of forward declarations to seemingly fail to compile for non-obvious
reasons. It also allows inlining of the construction/destruction logic
all over the place where a constructor or destructor is invoked, which
can lead to code bloat. This isn't so much a worry here, given the
services won't be created and destroyed frequently.

The cause of the above mentioned non-obvious errors can be demonstrated
as follows:

------- Demonstrative example, if you know how the described error happens, skip forwards -------

Assume we have the following in the header, which we'll call "thing.h":

\#include <memory>

// Forward declaration. For example purposes, assume the definition
// of Object is in some header named "object.h"
class Object;

class Thing {
public:
    // assume no constructors or destructors are specified here,
    // or the constructors/destructors are defined as:
    //
    // Thing() = default;
    // ~Thing() = default;
    //

    // ... Some interface member functions would be defined here

private:
    std::shared_ptr<Object> obj;
};

If this header is included in a cpp file, (which we'll call "main.cpp"),
this will result in a compilation error, because even though no
destructor is specified, the destructor will still need to be generated by
the compiler because std::shared_ptr's destructor is *not* trivial (in
other words, it does something other than nothing), as std::shared_ptr's
destructor needs to do two things:

1. Decrement the shared reference count of the object being pointed to,
   and if the reference count decrements to zero,

2. Free the Object instance's memory (aka deallocate the memory it's
   pointing to).

And so the compiler generates the code for the destructor doing this inside main.cpp.

Now, keep in mind, the Object forward declaration is not a complete type. All it
does is tell the compiler "a type named Object exists" and allows us to
use the name in certain situations to avoid a header dependency. So the
compiler needs to generate destruction code for Object, but the compiler
doesn't know *how* to destruct it. A forward declaration doesn't tell
the compiler anything about Object's constructor or destructor. So, the
compiler will issue an error in this case because it's undefined
behavior to try and deallocate (or construct) an incomplete type and
std::shared_ptr and std::unique_ptr make sure this isn't the case
internally.

Now, if we had defaulted the destructor in "thing.cpp", where we also
include "object.h", this would never be an issue, as the destructor
would only have its code generated in one place, and it would be in a
place where the full class definition of Object would be visible to the
compiler.

---------------------- End example ----------------------------

Given these service classes are more than certainly going to change in
the future, this defaults the constructors and destructors into the
relevant cpp files to make the construction and destruction of all of
the services consistent and unlikely to run into cases where forward
declarations are indirectly causing compilation errors. It also has the
plus of avoiding the need to rebuild several services if destruction
logic changes, since it would only be necessary to recompile the single
cpp file.

Aggregates multiple caches into one interface

We don't need to do the lookup if the path is considered empty
currently.

The follow-up to e2457418, which
replaces most of the includes in the core header with forward declarations.

This makes it so that if any of the headers the core header was
previously including change, then no one will need to rebuild the bulk
of the core, due to core.h being quite a prevalent inclusion.

This should make turnaround for changes much faster for developers.

Allows frontend to create registration caches for use before a game has booted.

Avoids the need to rebuild these source files if the mode header
changes.

Avoids the need to rebuild multiple source files if the filesystem code
headers change.

This also gets rid of a few instances of indirect inclusions being
relied upon