Remove PrimOps for high level lang

[anton-k]

I've noticed that we no longer need explicit constructors for high-level lang primops.

Otherwise we make redundant transformations.

• convert text to prim-ops constructors when parsing
• convert those prim-ops to text when doing inference and desugaring
• convert text to core prim ops

Instead we can keep them as text all the way up to conversion to core. Also it simplifies prelude alot and code for inference.