Closes #44

other fixes and linting

Repo structure complete redesign
Fixes #38

NoPostIfNotStaff permission added and userdata now returns the list of viewset that the user can post to.

Update backend : added FORCE_FULL_DISPLAY in serializer to return pending moderation elements as they are needed for the frontent in group view

Textfield ready
bug corrected

- comparaison when retreiving pending moderation wasn't done on the right elements
- Saving revision was done with user from request instead of updated by !

and return model

UniversitySemestersDates partially connected

Also removed some stuff

Cleared migrations
added LIST_SHOULD_BE_DETAIL in MyModelViewSet
cleaned get_viewset_permissions

Many bugs corrected !
Few tweaks