✨(models/api) add RBAC on templates linking accesses to a team name

We want to be able to control who can access a template via roles.
I added this feature on the TeamAccess model assuming that the teams
to which a user belongs can be retrieved via a `get_teams` method on
the user model. The idea is that this method will get the teams either
via a call to an external API or directly from the OIDC token upon
user login. This list of teams will probably have to be cached for
each user.

src/backend/core/admin.py

@@ -77,8 +77,3 @@ class TemplateAdmin(admin.ModelAdmin):
     """Template admin interface declaration."""
 
     inlines = (TemplateAccessInline,)
-
-
-@admin.register(models.Team)
-class TeamAdmin(admin.ModelAdmin):
-    """Team admin interface declaration."""