Add ability to upload avatars, not only upload links to avatars

[arvid220u]

This would require a solution similar to the one for #20, with a bucket containing all avatar images.

[n8kim1]

Do we not have this already in some capacity? Some teams are uploading raw picture data (at least that's what it seems like to me)

although yes, using buckets for these anyways rather than storing raw data would def be better