Possibility to show videos from different perspectives

[uklomp]

Hi @Jetske and @Woseseltops We talked about the possibility to upload multiple videos for signs and annotated sentences and to show this sign/sentence from multiple perspectives. We record the signs, and a new batch of annotated sentences (that are not from the corpus), with three cameras: one from the middle, like we upload now, one from the front-left and one from the front-right. We would like the following things:

1. A symbol in the video frame that users can click to see one of the other perspectives.
2. You asked before if this functionality of multiple perspectives would only be for single signs or also for annotated sentences --> we indeed also want this possibility for sentences, if it's not too difficult. --> Related to 2: If it's indeed possible for annotated sentences, the functionality regarding linked glosses should still work the same as it's working now, also when a video with a different perspective is shown.
3. We discussed what to do with search results, because then a small video from the front is shown: this will stay the same, we don't need the other perspectives here.
4. You asked what to do with deleting, moving, overwriting and you suggested to build two options: upload three videos at the same time, and upload/change only the middle video. We agree with this suggestion. In the second option, potential older videos from the left and right perspective remain, while the middle video is updated.