Update the used Flutter version to 3.16.5 and the used packages to their
latest version.
The Supabase package contained some breaking changes:
- `functionUrl` is not exported anymore, so that it must be generated by
ourselfs
- `Provider` was renamed to `OAuthProvider`
- The `signInWithApple` method was removed and is now implemented by us
via the `sign_in_with_apple` package.
We also renamed the `DesktopLoginManager` to `DesktopSignInManager` to
use the same naming as in other places of the app, where we are always
using sign in and not login.
It is now possible to play videos from toots within FeedDeck. For that
we are using the "madia_kit" package, which is already used for the
Podcast player on Windows and Linux.
The videos from a toot are saved within the "options.videos" field of an
item next to the "options.media" field. In the "ItemDetailsMastodon"
widget we are then checking if this field is present and contains a list
of video urls. These urls can then be played via the "ItemVideos"
widget.
Instead of using the "just_audio_windows" and "just_audio_mpv" packages
for Windows and Linux, we are now using "just_audio_media_kit", so that
the audio player is working reliable on these platforms.
Note: We have to adjust the Flatpak, to include the dependencies which
are required on Linux.
