Make uploaded files in admin UI searchable

[torgeirl]

Searching for temporary file (uploaded to server, but its comment haven't been sent yet) under Cradmin_Temporaryfileuploadstore › Temporary file collections in the Django admin UI it's search field doesn't work.

I assume we need to adjust the admin.py for it to work.

[espenak]

The problem here was that cradmin_legacy makes assumptions about the fields on the user model, and Devilry does not have those fields. I have patched that, and added a default for a new cradmin_legacy setting in devilry:

CRADMIN_LEGACY_DJANGOADMIN_USER_SEARCH_FIELDS = ["=shortname", "=id"]

This default makes it possible to search by exact shorname and id of the user in addition to searching for the exact id of the TemporaryFileCollection. The shortname is normally the same as the username.

The setting can be overridden to something like this:

CRADMIN_LEGACY_DJANGOADMIN_USER_SEARCH_FIELDS = ["shortname", "=id", "fullname"]

for a less strict search that includes the full name, but that will probably just make it harder to find files for a specific user because of more duplicate matches.