Respect tags while filtering for suitable tracks in Theodul player

Steps to reproduce:
1. Currently all videos are assumed as valis sources within the Theodul player
2. Only videos that are tagged with "engage-*" should probably be played.
3. It would be the best to have a configuration value that allows to select the tags and formats that should be used within the theodul player

Actual Results:

Expected Results:

Workaround (if any):