Support of special attribute updates in add_property

Summary

The Entity.add_property method now checks whether the name of an added property matches a special attribute and, if so, updates the attribute instead.
Addresses #217

Focus

• Should similar behaviour be supported for updates using only id? If so, how would I go about finding out which id the name attribute/property has server-side?
• As the method is called add_property and special attributes do not support multi-properties (as far as I know?), should we guard against an overwrite by only setting the attribute if it is currently None?

Test Environment

A unit test is included, is it sufficient?

Check List for the Author

• 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)
• 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?

src/linkahead/common/models.py

@@ -617,6 +617,10 @@ class Entity:
         If you want to add a property to an already existing entity, the
         property ``id`` of that property needs to be specified before you send
         the updated entity to the server.
+        If the specified name matches the name of a special attribute in
+        lowercase, such as 'name' or 'description', the attribute is set
+        instead. If the attribute already has a value, this fails with a
+        ValueError.
 
         Parameters
         ----------
@@ -666,6 +670,9 @@ class Entity:
             If you try to add an ``Entity`` object with File or Record role (or,
             equivalently, a ``File`` or ``Record`` object) as a property, a
             ``ValueError`` is raised.
+        ValueError:
+            If the property to be added is a special attribute and already has
+            a value.
 
         Examples
         --------
@@ -744,6 +751,21 @@ class Entity:
             raise UserWarning(
                 "This method expects you to pass at least an entity, a name or an id.")
 
+        # If the name is a special attribute, set the attribute instead
+        if name and name.lower() in SPECIAL_ATTRIBUTES and name.lower() in dir(self):
+            name = name.lower()
+            if getattr(self, name) is None:
+                setattr(self, name, value)
+                return self
+            else:
+                raise ValueError(f"'{name}' is a special attribute and does not "
+                                 f"support multi-property. It is already set "
+                                 f"and cannot be overwritten using this method. "
+                                 f"Please use direct assignment for setting this "
+                                 f"property after the first time.")
+        # ToDo: Implement the same behaviour for special attribute ids,
+        #       https://gitlab.indiscale.com/caosdb/src/caosdb-pylib/-/issues/219
+
         new_property = Property(name=name, id=id, description=description, datatype=datatype,
                                 value=value, unit=unit)