common/file_util: Fix and deprecate CreateFullPath, add CreateDirs

Fix CreateFullPath to have its intended previous behavior (whatever
that was), and deprecate it in favor of the new CreateDirs function.

Unlike CreateDir, CreateDirs is marked as [[nodiscard]] to avoid new
code ignoring its result value.

network, sockets: Replace `POLL_IN`, `POLL_OUT`, etc. constants with an `enum class PollEvents`

common/file_util: Make use of std::filesystem

Converts creation and deletion functions over to std::filesystem,
simplifying our file-handling code.

Notably with this, CopyDir will now function on Windows.

core: Remove unnecessary enum casts in log calls

applets: Resolve variable shadowing

Greatly simplifies our file-handling code for these functions.

ci: Remove `-DYUZU_USE_BUNDLED_UNICORN=ON`

Unicorn has been removed, yet CI still enables building with Unicorn.
This just cleans up a few leftovers by removing the variable from the
CMake parameters in CI.

memory: Resolve -Wdocumentation warning for Write()

Write() doesn't return anything, so the @returns tag shouldn't be
present.

configure_motion_touch: Fix unescaped backslash in regex

controller: Avoid unnecessary copies in ConfigurationComplete()

Follows the video core PR. fmt doesn't require casts for enum classes
anymore, so we can remove quite a few casts.

Avoids unnecessary copies.

Avoids unnecessary 1072 byte copies when querying info about
controllers.

Disable analog joystick from buttons by default

video_core: Make use of ordered container contains() where applicable

ast: Improve string concat readability in operator()

CMakeLists,network: Create YUZU_UNIX macro to replace __unix__

With C++20, we can use the more concise contains() member function
instead of comparing the result of the find() call with the end
iterator.

Provides an in-place format string to make it more pleasant to read.

map_interval: Change field order to address uninitialized field warning

shader_ir: std::move node within DeclareAmend()

buffer_block: Remove unnecessary includes

Prevents logic errors from occurring from unused values.

Reduces the amount of dependencies the header pulls in.

video_core: Remove unnecessary enum class casting in logging messages

core: Mark unused fields as [[maybe_unused]]

hle: Type check ResponseBuilder::Push arguments, and fix use in vi.cpp

Same behavior, but elides an unnecessary atomic reference count
increment and decrement.

fmt now automatically prints the numeric value of an enum class member
by default, so we don't need to use casts any more.

Reduces the line noise a bit.

nvdrv: Remove useless re-declaration of pure virtual methods that were already declared in the superclass

boxcat: Avoid unnecessary object copy

renderer_vulkan: Add missing `override` specifier

video_core: Resolve more variable shadowing scenarios pt.3

Since this is inside a string literal, backslashes that are part of
regex syntax have to be escaped.  But that's ugly, so convert to a raw
string instead.