Part of the `ScreenFooter` refactor, which intends to move the footer
content handling to `OsuScreen`. This commit updates the `ScreenFooter`
test to operate on entire `OsuScreen`s, in order to better test the
entire flow of pushing a screen, and having it create and add its own
content to the footer.
This should be 80-90% identical to the original test case structure
wise, just that instead of manually manipulating the footer with
`SetButtons()`, various screens with the appropriate buttons are being
moved around the screen stack.
Additionally this adds some more tests handling common use cases, as
well as removes `TestLoadOverlayAfterFooterIsDisplayed()`, since as far
as I understand the behaviour described in it doesn't actually happen in
production code. From what I can see, Screens instantiate their overlays
in `load()`, and then register them in `LoadComplete()`. There seems to
be no case where a `ShearedOverlayContainer` is created in the middle of
a screen's lifecycle.
This aims to bring some conformity to naming to make it easier to
understand component structure for new components.
Renames are pulled out of the song select v2 changes and are more
relevant there due to many new classes being added.
- `V2` suffix is dropped, with v2 components being moved to a relevant V2 namespace.
- Related classes have a prefix of the area they are used.
- Experimenting with using partial/nested classes in the song select v2 implementation.
Not committing to this yet but want to see how it plays out.
- Moved base carousel components to a generic namespace to avoid confusion with actual beatmap carousel implementation.