Merge branch 'housekeeping/upgrade-android-gradle-plugin-and-cleanup' into 'develop'

.../main/java/audio/funkwhale/ffa/activities/MainActivity.kt

...ain/java/audio/funkwhale/ffa/activities/SearchActivity.kt

...c/main/java/audio/funkwhale/ffa/adapters/AlbumsAdapter.kt

...in/java/audio/funkwhale/ffa/adapters/AlbumsGridAdapter.kt

.../main/java/audio/funkwhale/ffa/adapters/ArtistsAdapter.kt

...ain/java/audio/funkwhale/ffa/adapters/DownloadsAdapter.kt

...ain/java/audio/funkwhale/ffa/adapters/FavoritesAdapter.kt

...ava/audio/funkwhale/ffa/adapters/PlaylistTracksAdapter.kt

...ain/java/audio/funkwhale/ffa/adapters/PlaylistsAdapter.kt

...c/main/java/audio/funkwhale/ffa/adapters/RadiosAdapter.kt

...c/main/java/audio/funkwhale/ffa/adapters/SearchAdapter.kt

...c/main/java/audio/funkwhale/ffa/adapters/TracksAdapter.kt

...java/audio/funkwhale/ffa/fragments/AddToPlaylistDialog.kt

...main/java/audio/funkwhale/ffa/fragments/AlbumsFragment.kt

.../java/audio/funkwhale/ffa/fragments/AlbumsGridFragment.kt

...ain/java/audio/funkwhale/ffa/fragments/ArtistsFragment.kt

...n/java/audio/funkwhale/ffa/fragments/FavoritesFragment.kt

...a/audio/funkwhale/ffa/fragments/PlaylistTracksFragment.kt

...n/java/audio/funkwhale/ffa/fragments/PlaylistsFragment.kt

...main/java/audio/funkwhale/ffa/fragments/RadiosFragment.kt