Implicit module imports

[mark-koch]

Following the changes in #105, it would be nice if we could avoid gupply.load(...) calls and instead read of the imported Guppy modules from the Python environment.

from guppy import Qubit

@guppy
def foo(q: Qubit) -> Qubit:
   ...

guppy.compile()  # Sees that `Qubit` is in scope, so automatically imports the corresponding `quantum` module