add basis for Basemodel

[magsyg]

Added basis for new basemodel
Adds the fields created_at and updated_at to fetch when it was created and updated
Adds created_by and updated_by to track who updated it last
Also just a simple version field, which keeps track of each time it was updated

Added serializser and admin to support this

Wanted only to know if this was desired or not

[magsyg]

Almost the same as done in rekenett, good to keep track of when and who edited, for both frontend and backend

[magsyg]

Ignores mypyerror for CustombaseAdmin, since it is not explained wtf the inputs are in sourcecode https://github.com/django/django/blob/main/django/contrib/admin/options.py

[magsyg]

Tar dette som dette kan prøves å kjøres inn, nice

[Snorre98]

LGTM