Support for player controls (play, pause, volume control)

Prior to this, once paused, would get stuck at receiving the frame
since the receiver sleeps when nothing is available, thus no events
are polled. By receiving only when playing, this eliminates the issue.

NOTE: cannot use `try_recv()` since it would lead to flickering when
this thread is running faster than the audio producing thread.

This prevents the problems of floating point, usually the person just
wants to adjust the percentage, doesn't care about the actual ratio.

Allow user to set volume.

This allows using `KeyCode::Char(' ')` to play and pause.

This adds play, pause & playpause functionality. The media keys
haven't been tested but in theory should work.

This is so that media controls work when implemented.

`minimp3` used to depend on `slice-deque` which is unmaintained and
contains memory safety issues, see
https://github.com/germangb/minimp3-rs/issues/42

`minimp3` now uses `slice-ring-buffer`

the closing bracket was missing from the CI badge

feat: add systemd service commands

chore: package for ubuntu/debian and fedora

ci: include README.md and LICENSE to the final archive

ci: install protoc from homebrew

feat(api): add provider to request parameters

feat(api): call a generic radio provider

fix(ui): handle unknown station name and bitrate

feat(provider): add new radio provider: radio-browser