mlv_lite and mlv_rec are highly redundant, should be merged

[reticulatedpines]

Both mlv_lite and mlv_rec perform very similar functions. Functionality should be merged while keeping acceptable performance. If necessary, optional expensive functionality could be behind a toggle in a menu (metadata per frame?).

First need to determine required functionality (mlv_rec does more, except, mlv_lite does lossless compression... anything else it's better at?). Card spanning is important. Both should do sound, need to confirm this.

Some discussion of differences here: https://discord.com/channels/671072748985909258/671072748985909264/1142858075682906132