Bumped version to 1.5.3
As a part of the task T50726:
Update the Panel rename code to more generic one

PEP8 cleanup:
Tuple imports and use them for class types
Consistent Scene props definitions

Flake8 reports two variables being unused:
line 345 - scene
line 347 - select_obj
Haven't removed them yet as that needs some clarification
about their purpose