Resolve "Fix mypy errors in models.py and complete type hints"

Summary

This MR fixes many type errors in models.py reported by mypy (Related to #191 (closed))

Focus

• Potential Nones are now handled wherever mypy reported them
• Please check the correctness of IMPORTANCE vs INHERITANCE (see also server docs)
• New type hints for Query, QueryTemplate
• Two open issue remain (see below).

Test Environment

Regular

Check List for the Author

Please, prepare your MR for a review. Be sure to write a summary and a focus and create gitlab comments for the reviewer. They should guide the reviewer through the changes, explain your changes and also point out open questions. For further good practices have a look at our review guidelines

• All automated tests pass
• Reference related issues
• Up-to-date CHANGELOG.md (or not necessary)
• Up-to-date JSON schema (or not necessary)
• Appropriate user and developer documentation (or not necessary)
  • How do I use the software? Assume "stupid" users.
  • How do I develop or debug the software? Assume novice developers.
• Annotations in code (Gitlab comments)
  • Intent of new code
  • Problems with old code
  • Why this implementation?

Check List for the Reviewer

• I understand the intent of this MR
• All automated tests pass
• Up-to-date CHANGELOG.md (or not necessary)
• Appropriate user and developer documentation (or not necessary)
• The test environment setup works and the intended behavior is reproducible in the test environment
• In-code documentation and comments are up-to-date.
• Check: Are there specifications? Are they satisfied?

For further good practices have a look at our review guidelines.

src/linkahead/common/models.py

@@ -474,14 +474,14 @@ class Entity:
             priority=priority)
 
     def is_permitted(self, permission: Permission, role: Optional[str] = None):
-        if self.acl is None:
-            raise EntityHasNoAclError("This entity does not have an ACL (yet).")
-
         if role is None and self.permissions is not None:
             # pylint: disable=unsupported-membership-test
             return permission in self.permissions
+        else:
+            if self.acl is None:
+                raise EntityHasNoAclError("This entity does not have an ACL (yet).")
+            self.acl.is_permitted(role=role, permission=permission)
 
-        self.acl.is_permitted(role, permission=permission)
 
     def get_all_messages(self) -> Messages:
         ret = Messages()