While we are at it, remove nullptr checks for deletion, since the C++
standard defines that delete does it by its own

With the loading screen merged, we don't want to actually show at this
point, but it still needs to be shown to actually create the context.
Turns out you can just show and hide it immediately and it'll work.

Loading progress bar upgrades

QT Frontend: Add a Loading screen with progressbar

gl_rasterizer_cache: Use dirty flags for framebuffers

gl_rasterizer: Use DSA for VAOs and buffers

yuzu/configuration/configure_web: Amend verification string

loader: Add getters for application banner and logo

With shader caches on the horizon, one requirement is to provide visible
feedback for the progress. The shader cache reportedly takes several
minutes to load for large caches that were invalidated, and as such we
should provide a loading screen with progress.

Adds a loading screen widget that will be shown until the first frame of
the game is swapped. This was chosen in case shader caches are not being
used, several games still take more than a few seconds to launch and
could benefit from a loading screen.

yuzu/web_browser: Minor cleanup

gl_rasterizer: Silent unsafe mix warning

file_sys/directory: Remove unused DirectoryBackend class

This isn't used at all, so we can just get rid of it.

'this' isn't actually used within the lambda, since what we need
from the class is already assigned within the capture section of
the lambda.

It's a common UI pattern to use an ellipsis to indicate an ongoing
action, rather than just specifying the word by itself.

Gets rid of a few indirect inclusions.

This is a function that definitely doesn't always have a non-modifying
behavior across all implementations, so this should be made non-const.

This gets rid of the need to mark data members as mutable to work around
the fact mutating data members needs to occur.

Avoids the need to potentially reallocate the contained callbacks.

These currently aren't used by anything other than the QtWebBrowser
class itself, and can be made private.

audio_core: remove unnecessary spaces on comments

game_list: Remove a reference of a reference