Implement parametric polymorphism

[Technius]

Includes:

• Parametric polymorphism in functions
• Rank 1 type constructors
• Fix constructor memory allocation (previously allocated 0 bytes, I think)
• Polymorphism is implemented by passing values in a "tag"/box wrapper during runtime. Primitive values such as integers, booleans, and ADTs are boxed during conversion from AST to JoinIR.

Caveats:

• Arguments to a function reference are not automatically boxed/unboxed yet. This requires creating wrappers for function references if boxing/unboxing is needed (e.g. a generic filter function over a concrete linked list).