2.2.0

Release Nageru and Futatabi 2.2.0.

  - Support AV1 output, via SVT-AV1. Note that this is still somewhat
    experimental, not the least because SVT-AV1's streaming support
    is not as mature as x264.

  - Remove the dependency on QCustomPlot.

  - Expose BlurEffect and UnsharpMaskEffect to the theme.

  - Clean up several rarely-unused command-line flags:
    - All the 10-bit flags are now collapsed to --10-bit.
    - Remove --http-uncompressed-video.
    - Remove the x264 VBV flags.
    - Hide --x264-speedcontrol-verbose.
    - Hide --no-flush-pbos.

  - Make a workaround for audio monitoring output under PipeWire.

  - Update CEF compatibility (tested with CEF 107).