Beta time has come ! 🎉

WARNING: migrations have been reset one last time!

This MR concerns tones of little tweaks:

Reviewed:
* model moderation levels
* serializers.meta.fields value
* Viewset permissions
* on_delete values

Changed:
* Update dark theme color
* Added load prod base script
* beta logo on website
* Added missing about project markdown
* Added RGPD notice to all forms
* Put media files in a docker volume
* More frequent currency exhange rates update

Fixed:
* Front handling of scholarships
* Currencies conversion in the front
* Front theme icons color
* No default networks in prod docker compose to prevent nasty VM routing

Closes #135 #119 #96

* Added new BaseModel /serializer/viewsets
* Change names of abstract models/serializers/viewsets
* Folder structure changed in tha backend
* Added some backend test
* Corrected bug related to moderation on non versionned modeles
* Corrected bug related to no post permissions
* Updated doc accordingly

Fixes #91

Some of them were simply removed, oter were fixed.
From now on, the use of TODO is not permitted in the code.

Added has_pending_moderation attribute
Tests also updated

Closes #44

Repo structure complete redesign
Fixes #38

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

Errors are returned as JSON when used with API