Fixed T23807

Summary:
Added PropertyKeyPath class and tests

Signed-off-by: Ralf Floca <r.floca@dkfz-heidelberg.de>

removed redundant include

Signed-off-by: Ralf Floca <r.floca@dkfz-heidelberg.de>

Test Plan: Implemented unit tests

Reviewers: O1 MITK Core, kislinsk, goch

Reviewed By: O1 MITK Core, kislinsk, goch

Subscribers: goch, kislinsk

Maniphest Tasks: T23807

Differential Revision: https://phabricator.mitk.org/D91