feat: Add a pretty printer

[ontomaquia]

Expected features:

• Use unicode characters (lambdas, forall, arrows, etc) (Flag?).
• Non dependent products should be printed as arrow types.
• Print parenthesis only when needed.
• "Uncurryficate" lambdas and products (Flag?):

fun (x : A). fun (y : A). fun (z : B). x
# should be printed as
fun (x y : A) (z : B). x

• Separate big outputs into multiple lines in a sensible manner.