This adds a medium (500px) size avatar thumbnail, that can be
referenced as `{name}-medium.png`. It is intended to be used on the
user's own settings page, though we may come up with other use cases
for high-resolution avatars in the future.
This will automatically generate and upload the medium avatar images
when a new avatar original is uploaded, and contains a migration
(contributed by Kirill Kanakhin) to ensure all pre-existing avatar
images have a medium avatar.
Note that this implementation does not provide an endpoint for
fetching the medium-size avatar for another user.
[substantially modified by tabbott]
Also, fixed a a small type annotation in users.py because email must
be a string because emails don't support UTF-8 at this time (according
a comment in gravatar_hash in avatar.py).
This function doesn't require the whole UserProfile object to
create the avatar url, and we call it from Message.to_dict_uncached().
(imported from commit e814caab101c4fedd1ba66df041a3408014e4085)
This needs to be deployed to both staging and prod at the same
off-peak time (and the schema migration run).
At the time it is deployed, we need to make a few changes directly in
the database:
(1) UPDATE django_content_type set app_label='zerver' where app_label='zephyr';
(2) UPDATE south_migrationhistory set app_name='zerver' where app_name='zephyr';
(imported from commit eb3fd719571740189514ef0b884738cb30df1320)