Juno Improvements: type inference and intrinsics

• Add float kind to allow functions polymorphic over any float type (useful with our many float-only intrinsic functons)

• Make type arguments optional on parametric types, functions, and intrinsic functions and add type wildcards

• Modify type checking and inference to handle optional type arguments and type wildcards, improve handling of unconstrained types and produce errors if types remain unsolved

• Add the Hercules intrinsic functions to Juno and implement code generation

juno_frontend/examples/intrinsics1.jn

+fn intrinsics1(x : f32, y : f64) -> f64 {
+  return sqrt!(x) as f64 + sqrt!(y);
+}