Start Ligen Universal Parser

[notdanilo]

Ligen Universal Parser is a parser for universal syntaxes:

attribute := identifier = <constraint> // constraint is a Generic Parseable Type. e.g.: Literal, Expression... The Generic Parseable Type can be natively implemented by Ligen Universal Parser like Literal and Expression, or can be created by the library user.

[notdanilo]

Move universal implementations out of ligen-rust-parser and ligen-python-parser to ligen-universal-parser

[notdanilo]

This was implemented