Introducing first class Product and Record types

[bladyjoker]

DONE

• Updates the API with the new Product and Record messages and removes the joint Product type. Ofc these are now accepted as TyBody
• Updates the Compiler to handle product and record types (kind check and class constraint checks).
• Update the Frontend with the new syntax.
• Updates the Codegen to handle product and record types (checks and prints).
• Updates the lbg with a proper interface lbg gen-haskell -i lambda-buffers.input.textproto -o lambda-buffers.output.textproto -p autogen
• Cleanup.