We do use the pytest-django plugin to manage the django db setup magic,
so with this change, we can run tests without an existing db, or starting
a postgres db dedicated to the tests using pifpaf.

related to T1261

Summary: Part of T1261

Test Plan: Still running 104 tests after the change

Reviewers: ardumont

Differential Revision: https://forge.softwareheritage.org/D525

Related T1169

Related T1169

Ids can be other types than string, join will not work on those.
This commit fixes it.

Close T1154

Related T1154

This unifies the way we parse xml server side and client side.

Related D396#inline-1961

Add the synthetic revision id as ancillary information

Related T1152

Close T1153

Related T1123

As possibly multiple associated archive(s) check(s) can happen now.

Related T1123

Related T1123

Related T1123

We were adding all tested fields tested while we wanted only to keep
the ones matching 'url'.

Related T1010

So far, the status detail was generic. In case of rejected deposit, we
now provide the detailed explanation of the failed checks.

Related T1010

Related T1010

Close T1010

This takes care of current limitations:
- duplicated elements are stored as list (and no longer dropped)
- drop extra namespace in key names
- it's generic

Close T1131