Video uploads

[bobintetley]

With the amount of work that has been done to push file storage off to a CDN asynchronously, it would now be possible for us to support direct video uploads where we could not previously.

Places affected by this that I can think of off the top of my head:

media.js (support file type and size limit, 10MB? Default video indicator)
media.py (handle storage, may not need anything doing)
petrescue.py (include preferred video in photo_urls)
service.py (animal_video call needs implementing to get the preferred)
dbfs.py (local cache time should be shorter for videos, eg: 2 days)

SM service handler wants to make sure the CDN is caching video downloads served via the animal_video service call with a decent ttl.

Unrelated directly to the task, but we could also look at reviewing our storage costs/rates/tiers and make it a bit cheaper.

[bobintetley]

making data available for download for users who want to migrate away is a consideration - the users who want videos on incidents could really inflate their storage use with this.

[bobintetley]

Other questions. Do we need to extract thumbnails from videos? What video formats are we going to accept? Some of the driver of this is PetRescue - what video formats do they accept?

[bobintetley]

For simplicity, maybe only accept mp4 container videos with a file size limit of 10MB per video. Probably make accepting video an option that is off by default since it will make it easy for people to run up storage bills quickly.