Redesign parser and rule model

[aannleax]

The current parser should be reworked to parse into a dedicated AST representation of the program, which then gets translated into a logical model. The latter should keep track of the origin nodes in the AST to be able to generate nice error message that reference the specific line in the source code.

• [x] Create a AST model
• [x] Write a parser that returns that AST
• [ ] #511
• [x] #516
• [x] #512
• [ ] #513
• [ ] #517
• [ ] #521
• [ ] #522
• [ ] #523
• [ ] #524
• [ ] #528