libcamera: Adjust postview for rear camera.

Rear facing camera breaks with the new POSTVIEW values. Reduce
them back if rear cam is in use.
media_profiles: Partial fixes for video recording.

Recent camera updates seem to have broken the use of high/low.
Switch naming (although rear cam is not actually recording in 720p)
to fix front cam recording and high quality rear camera recording.
Lower quality rear camera recording needs fixing.