Add mcz, mcp and crz to QuantumCircuit

[purva-thakre]

The Qrisp documentation provides a list of operations that can be added to an object of the QuantumCircuit class.

If the mcz, mcp or crz gates are added to a quantum circuit, we get AttributeError: 'QuantumCircuit' object has no attribute 'mcz'/'mcp'/'crz'. This PR adds the missing gates as methods of the QuantumCircuitclass.

from qrisp import QuantumCircuit
qc = QuantumCircuit(4)
qc.cx(0, range(1,4))
qc.mcz([0, 1], 3)
print(qc)

In the above code block, replace mcz with mcp or crz.

Edit: Spoke with Raphael on this. The gates that can be applied to the QuantumCircuit class are different from the gate functions on the linked page in the documentation. I don't know if it's worth adding these gates....

To do: mcrx exists in standard_operations.py but not as a method of the QuantumCircuit class.

[positr0nium]

Thanks for tackling this! To align the implementation of QuantumCircuit.mcp and QuantumCircuit.mcz more with the standalone functions mcp and mcz, I think it would be beneficial to remove the target argument 👍