Clif ir and vcode/asm inspector

[bjorn3]

This inspector allow you to pick a single function and then present the clif ir (before and after optimization) and compiled vcode/asm of said function. It should also show the mapping between clif ir and vcode instructions in a way similar to godbolt's compiler explorer. As a bonus it could also show the original rust source and the mir of the compiled function. Preferably the inspector would be usable for other Cranelift users too if they dump all necessary info in the right format.