Code quality could be better

[Jagholin]

I know that the bar for GDScript code is not very high, and I consider myself quite tolerant when it comes to other's people code, but there are a couple of issues here that make me not want to even touch this plugin:

1. You like using Dictionarys way too much. I feel like 99% of the dictionaries in this code should just be replaced with classes for better readability and maintainability
2. You inherit the classes that you have from very strange bases, like PackedDataContainer. I'm not sure you understand what this class even does, but inheriting from it does absolutely nothing in this context. You should inherit from Resource or better yet RefCounted if you don't need any of the Resource's functionality.

There are other strange things that I noticed, but those are relatively minor. Fixing just these 2 should not take a lot of time and will immediately improve code quality by an order of magnitude, from my point of view at least