Add video recording

Issue taken from postmarketOS/megapixels#7 and https://todo.sr.ht/~martijnbraam/Megapixels/20.

Megapixel's picture quality is great but it doesn't do video recording. Ideally it would make use of the PinePhone's H264 hardware encoder (1080p60 capable) with similar or identical picture quality.

~martijnbraam
For the quality it currently uses a bayer mode from the sensor, for video recording it would need to use the YUV mode to feed the data in realtime to the hardware encoder. The main thing that needs to be done is figuring out how to apply the color matrix in that case since that would be one of the main improvements for the picture quality.

Additional notes:

An option to choose 720p at 30 FPS would also be interesting to reduce file size.

Video recording should be made possible like done on these forks:

https://gitlab.com/tui/millipixels

https://gitlab.com/tui/Megapixels2 (https://social.kernel.org/notice/AhFxeCMdslrRIhQjE8)

Currently there are errors when trying video recording with all existing scripts, so I had to do screen recording of the Megapixels app: Alaraajavamma/fastvideo#7