Reload fix

[brachy84]

There was an issue where classes on reload can randomly not be found without any consistent reproducability.
In an attempt to fix this a custom GroovyScriptEngine and GroovyClassLoader has been implemented in this pr.
Both of these classes had their own caching mechanic which might have clashed in some way. This caching is now removed.

• The script caching from GroovyScriptSandox moved to CustomGroovyScriptEngine
• GroovySandbox class is removed as abstraction doesnt make sense here
• GroovyScript now handles script dependencies properly: When a script references another script, its automatically loaded
• classes are no longer special cases in the run config
• since script deps are auto loaded, classes only need to be specified if they contain any static code that needs to run
• the custom impl also allows removing 2 mixin classes