Store instantiated canvas layers in dictionary keyed to an enum

[calvinchd]

Added a dictionary to track instantiated nodes keyed to the new EffectType enum. Removes the need to use node names to identify which effect the node belongs to.

Fixes

The names of the instantiated nodes seems to change during runtime resulting in the "Undefined type Post Processing addon - verify it has been properly integrated. error. Since we're not longer using the node names, this error message is no longer applicable and the related issues should be fixed.

• core/variant/variant_utility.cpp:1092 - #Undefined type Post Processing addon - verify it has been properly integrated. #28
• My project is crashing when loading a project that I'm using the addon #19

Related

• Suggestion : move to a match statement for _check_shader_visibility() #24