Option to display a photo if webcam stream is not enabled

[VauHa]

In large meetings the use of webcams is often omitted in order not to run into bandwidth problems. In this case a user provided photo could help to improve the atmosphere of the meeting. One could think of several options:

• display the photo instead of the camera feed, either continuously or when the user is speaking
• show the photo in the participants list (even independant from the webcam stream)

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[ffdixon]

This is a good suggestion -- we should have an 'avatar' mode for webcams, which displays either the webcam, initials, or avatar picture (if available).

[prlanzarin]

Duplicate of #13844 and related to #12481