Fixes Disgaea 6 Demo issues.

Also adds documentation for the ReadSetting function.

Address review comments.

Co-authored-by: Mai M. <mathew1800@gmail.com>

bcat: Fix settings access

telemetry_session: Fix settings accesses

So this is what I get for testing with the web service disabled.

touch_from_button: Fix settings access for clang

For simple primitive settings, moves their defaults and labels to
definition time.

Also fixes typo and clang-format

yuzu qt: config: Fix rng_seed

Creates a new BasicSettings class in common/settings, and forces setting
a default and label for each setting that uses it in common/settings.
Moves defaults and labels from both frontends into common settings.
Creates a helper function in each frontend to facillitate reading the
settings now with the new default and label properties.

Settings::Setting is also now a subclass of Settings::BasicSetting. Also
adds documentation for both Setting and BasicSetting.

Avoids double-setting defaults, and avoids potential accidents when
inconsistently setting the default on new settings.

Requires a default value when creating each per-game setting.

vulkan_device: Make device memory match the rest of the file

Match the style in the file.

astc: Various robustness enhancements for the gpu decoder

common: Replace common_sizes into user-literals

Removes common_sizes.h in favor of having `_KiB`, `_MiB`, `_GiB`, etc
user-literals within literals.h.

To keep the global namespace clean, users will have to use:

```
using namespace Common::Literals;
```

to access these literals.

general: Add missing #pragma once directives

* Add missing includes

* Add array

externals: Update fmt to 8.0.0

[audout] Implement GetAudioOutPlayedSampleCount

Also removes some deprecated API usages.

maxwell3d: Add missing return in default SizeInBytes() case

We were returning '1' in ComponentCount()'s default case but were
neglecting to do the same with SizeInBytes().

GPU: Implement a garbage collector for GPU Caches (project Reaper+)

Keeps us up to date with the latest major release.

Also allows compilers that support it to perform compile-time format
string checking.

bootmanager: Use std::stop_source for stopping emulation

Simple resizing of Per-Game configuration window and removal of useless Help question mark button in the title bar

common/detached_tasks: Wait for tasks before shutting down

input_common/mouse_input: Fix data race

npad: Fix data race when updating devices

Simple resizing of the Per-Game configuration window and removal of useless Help question mark button in the title bar

common: fs: Miscellaneous changes

service: spl: Implement general SPL service

service: time: Use GetFileRelative to get files within subdirectories

This provides a more concrete example of what a regular file is and isn't.

These enforce requiring the file to exist prior to opening.

This check was preventing files with the Write or Append file access modes from being created, as per the documented behavior in FileAccessMode.
This amends the check to test for the existence of a filesystem object prior to checking whether it is a regular file.
Thanks to liushuyu for pointing out that removing the check altogether would not guard against attempting to open non-regular files such as directories, symlinks, FIFO (pipes), sockets, block devices, or character devices.
The documentation has also been updated for these functions to clarify that a file refers to a regular file.

Similarly, Flush() is typically called to attempt to flush a file into the disk. In the one case where this is used, we do not care whether the flush has succeeded or not, making [[nodiscard]] unnecessary.