Encoder: Add EncodingPreference

This adds a new enum called EncodingPreference with following values

• NoPreference

  • Veryfast preset, no tune
  • Default usecase

• Quality

  • Medium preset, no tune
  • Good for high quality video

• Speed

  • Ultrafast preset, zerolatency tune
  • Good for streaming

• Size

  • Slow preset, no tune
  • Should be the smallest size when encoded

• Check is the film tune required for Quality pref