Define desired features for old cams

[reticulatedpines]

What features currently absent from this repo, should exist on old cams, before we can release builds for them?

Possible features:

• increased MOV time limit
• improved real-time preview (ported from Bilal's work, and/or Arnaud's)
• improve included cropmarks
• sd_uhs.mo
• others? Add in comments

The simplest option would be to keep old cams as is. Personally, I'd like to add some new things, to give people a reason to update. If we can justify the time to port Bilal's preview stuff, that might reduce the number of builds we have to support.

Popular features that exist in forks or old-official branches, especially ones that are well tested, are good candidates.

This ticket is for discussion in order to define scope. When discussion is finished, new tickets should be made for the work and this ticket closed.