#101 Team sharing form

* adds team sharing field to share form
* splits sharing logic into user based and teams based
* adds TeamAdmin for admin backend
* adds validity check on Team name -> only unused names shall be valid

compensation/tests/payment/test_workflow.py

@@ -21,7 +21,7 @@ class PaymentWorkflowTestCase(BaseWorkflowTestCase):
     def setUp(self) -> None:
         super().setUp()
         # Give the user shared access to the dummy intervention
-        self.intervention.share_with(self.superuser)
+        self.intervention.share_with_user(self.superuser)
 
         self.payment = Payment.objects.get_or_create(
             intervention=self.intervention,