Add additional setting for disabling video cropping

Currently, the video received from other participants in a call is cut off to fit the screen. This can cause problems, if the other participant has a laptop / tablet, which usually produces a video in a 4:3 or 16:9 format. If one is using a smartphone held vertically the video will be cut off at both sides. If the other participant is in the center of the video, it will be fine as only unimportant parts of the video are cut off. However if two participants are in the video, usually one of them will be cut out or both of them.
The solution is to rotate the smartphone to get a better view. However in some situations it can be preferred to keep the smartphone vertically.
It would be nice, if a option would be included, which allows to always show the full video of the other participant. The current behavior could be the default one, but users should be able to disable the cropping if they don't prefer it.

The issue names no files or tests. Start by tracing the Android call video rendering and settings entry points, then determine how an option can preserve the full incoming video while retaining cropping by default; done means the preference works for vertically held phones and multi-person video.