What should we add?

Currently we have the methods mcrx, mcry and mcrz in the QuantumCircuit class, but they don't appear in the circuit library.
I would suggest to add them to the circuit library as the other multi-controlled gates.

In addition, in order to make a unified API as the other multi-controlled gates, these gates should include the following:

1. The angles should be of type ParameterValueType (not only float).
2. Add ctrl_state parameter (like in MCXGate).
3. The control method of the rx, ry and rz gates, should call the MCRX, MCRY or MCRZ gates respectively (if there are more than two qubits)