Keeps everything under the same namespace. While we're at it, enclose
them all within an inner anonymous namespace.

In all cases, a virtual address is being passed in, not a physical one.

General moving to keep kernel object types separate from the direct
kernel code. Also essentially a preliminary cleanup before eliminating
global kernel state in the kernel code.

Ensures both operands in comparisons are the same signedness.

* More improvements to GDBStub
- Debugging of threads should work correctly with source and assembly level stepping and modifying registers and memory, meaning threads and callstacks are fully clickable in VS.
- List of modules is available to the client, with assumption that .nro and .nso are backed up by an .elf with symbols, while deconstructed ROMs keep N names.
- Initial support for floating point registers.

* Tidy up as requested in PR feedback

* Tidy up as requested in PR feedback

* GDB Stub should work now.

* Applied clang-format.

* Replaced htonll with swap64.

* Tidy up.

This gets gdbstub working at least to the point where clients can
communicate with it.

What works:
- Reading/writing GPRegs
- Reading/writing memory
- Interrupting the emulated program and continuing

What does NOT work:
- Breakpoints. Sizes have been updated to u64, but support will need to be
  added in the interpreter for them to work.
- VRegs. Mostly because my gdb was having issues with 128-bit regs for
  some reason. However, the current u128 representation is a bit
  awkward to use and should probably be updated first.

* Fixes some cast warnings, partially fixes citra #3064

* Converted casts to uint32_t to u32

* Ran clang-format

Core::System().GetInstance().IsPoweredOn() -> Core::System::GetInstance().IsPoweredOn()

Corrects a few issues with regards to Doxygen documentation, for example:

- Incorrect parameter referencing.
- Missing @param tags.
- Typos in @param tags.

and a few minor other issues.

Also uses size_t as the length indicator type, as is common with buffers.

Currently, this is only ever queried, so adding a function to check if the
server is enabled is more sensible.

If directly modifying this externally is ever desirable, it should be done
by adding a function to the interface, rather than exposing implementation
details directly.

This makes clang-format useful on those.

Also add a bunch of forgotten transitive includes, which otherwise
prevented compilation.

This fixes the comments left on the PR (whitespace, SO_REUSEADDR,
comment changes).