- added `startAt` and `endAt` optional timestamps to help pin down reported sections of a video
- added predefined report reasons
- added video player with report modal
* Add video file metadata via ffprobe
* Federate video file metadata
* Add tests for file metadata generation
* Complete tests for videoFile metadata federation
* Lint migration and video-file for metadata
* Objectify metadata from getter in ffmpeg-utils
* Add metadataUrl to all videoFiles
* Simplify metadata API middleware
* Load playlist in videoFile when requesting metadata