qasm3_to_qir support for subroutines

[ryanhill1]

Add support for converting OpenQASM 3 program which contain subroutines to QIR.

qbraid-qir/qbraid_qir/qasm3/visitor.py

Lines 773 to 774 in 08554ce

	elif isinstance(statement, SubroutineDefinition):
	raise NotImplementedError("OpenQASM 3 subroutines not yet supported")

Placeholder test cases: test_subroutines.py

e.g.

OPENQASM 3.0;
include "stdgates.inc";

def apply_h_and_measure(qubit q) -> bit {
    bit result;
    h q;
    measure q -> result;
    return result;
}

qreg q[1];
creg c[1];

c[0] = apply_h_and_measure(q[0]);

openqasm reference for implementing subroutines