Load circuit as a function definition

[ss2165]

So that function value execution isn't required

Use uuids for circuits - can use circuit names or custom names in future once we have #563 and use that for circuits

[mark-koch]

We want to allow users to declare pytket circuits to be used within Guppy at the module level:

from pytket import Circuit

pytket_circ = Circuit(2)
pytket_circ.H(0)
pytket_circ.CX(0, 1)

@guppy.pytket(pytket_circ)
def guppy_circ(q1: qubit, q2: qubit) -> None:
   """Explicit stub for the circuit."""

# Alternatively, we also want to support loading without declaring a stub
guppy_circ = guppy.load_pytket(circ)

@guppy
def main() -> None:
   q1, q2 = qubit(), qubit()
   guppy_circ(q1, q2)
   measure(q1)
   measure(q2)

The benefit of the stub approach is that it will allow the user to specify whether they want to use arrays for registers or pass qubits one by one.

To implement this feature, we need to add new kind of Definition:

• RawPytketDef that holds a reference to the Python stub function and implements ParsableDef. The parse method should check that the provided stub signature makes sense for the circuit.
• ParsedPytketDef that holds the parsed circuit signature and implements CallableDef and CheckableDef. guppy.load_pytket should directly lower to that.
• CompiledPytketDef that holds a reference to the Hugr FuncDefn that was generated for the circuit and implements CompiledCallableDef.

In decorator.py, we need to add the appropriate guppy_circ and load_pytket functions that construct a RawPytketDef or a PytketDef respectively, and register it with the current module.