#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/compensation/test_workflow.py

@@ -25,7 +25,7 @@ class CompensationWorkflowTestCase(BaseWorkflowTestCase):
         super().setUp()
 
         # Give the user shared access to the dummy intervention -> inherits the access to the compensation
-        self.intervention.share_with(self.superuser)
+        self.intervention.share_with_user(self.superuser)
 
         # Make sure the intervention itself would be fine with valid data
         self.intervention = self.fill_out_intervention(self.intervention)