Migrate to androidx-media3 video player (#3857)
Behaviour is consistent with previous player except that:
- Swapping apps while a video is playing, and then returning to Tusky,
will keep the seek position in the video instead of returning to the
start
- The controls/media description can be shown by tapping anywhere, not
just on the video itself
- The media description is on-screen for the same duration as the player
controls (5 seconds here, 3 seconds in the previous code)
- The user has options to control the playback speed
- Rotating the device does not squash/stretch the video
- Show the media preview when playing audio-only files
Fixes https://github.com/tuskyapp/Tusky/issues/3329,
https://github.com/tuskyapp/Tusky/issues/3141,
https://github.com/tuskyapp/Tusky/issues/3126,
https://github.com/tuskyapp/Tusky/issues/2753,
https://github.com/tuskyapp/Tusky/issues/3508,
https://github.com/tuskyapp/Tusky/issues/3291
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Co-authored-by: mcc <andi.m.mcclure@gmail.com>