Door object has hardcoded customizable properties

[thaije]

Describe the bug
The Door object has its customizable properties hardcoded: https://github.com/matrx-software/matrx/blob/master/matrx/objects/standard_objects.py#L71

This should be changed such that it can be set by the user as well. It is primarily a problem as the WorldBuilder.add_room allows passing the door_customizable_properties, which are then thus ignored.

To Reproduce
Create a door with a property such as img_name, pass img_name as well in the customizable_properties, and try the img_name in an action with door.change_property("img_name", "new_img_name.png". This change is ignored.

Expected behavior
Door object can be passed a customizable_properties list that it listens to.

[thaije]

@BirgitvdS this is your issue