#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

api/tests/v1/create/test_api_create.py

@@ -109,8 +109,8 @@ class APIV1CreateTestCase(BaseAPIV1TestCase):
         Returns:
 
         """
-        self.intervention.share_with(self.superuser)
-        self.eco_account.share_with(self.superuser)
+        self.intervention.share_with_user(self.superuser)
+        self.eco_account.share_with_user(self.superuser)
 
         url = reverse("api:v1:deduction")
         json_file_path = "api/tests/v1/create/deduction_create_post_body.json"