Support `qiskit.qasm3.dumps` for circuits with IonQ native gates

[ryanhill1]

What feature would you like to see added? Why is it valuable?

Support conversion of circuits with IonQ native gates to OpenQASM 3

What is the expected behavior, in detail?

import openqasm3.parser
import qiskit
import qiskit.qasm2
import qiskit.qasm3
import qiskit_ionq

circuit = qiskit.QuantumCircuit(1)
circuit.u(0.1, 0.2, 0.3, 0)

provider = qiskit_ionq.IonQProvider()

backend = provider.get_backend("simulator", gateset="native")

transpiled_circuit = qiskit.transpile(circuit, backend=backend)

qasm3_str = qiskit.qasm3.dumps(transpiled_circuit)

Can you help make this feature a reality? By yourself? If not, what support would you need?

It's already implemented for qasm2 so hopefully shouldn't be that hard