.aeon format rework

[daemontus]

There are several problems with .aeon format right now:

• There is no way to output variables without regulations (you can make a fake "self" regulation that does not change anything, but this is very wrong).
• Parameters are implicitly declared based on update functions - this is error prone.
• There is no support for multiline or composite expressions (or more complex things like switches).
• The support for metadata is very lax and parsing them is very restricted.
• No rich-text editor for aeon format.

Currently, there is some work in model-toolkit which might be a better starting point for a format like this, but everything there is mostly aimed at continuous/hybrid systems and written in Kotlin. However, it might actually be good to make a hybrid format for everything because we need to handle hybrid systems as well. However, there should be some kind of built-in validation for things like that (i.e. I can declare a certain file to be a boolean network and that means extra validation rules).