Support for measurements operations

[obliviateandsurrender]

This adds functionality to support measurements present in a qiskit's QuantumCircuit object or allows to override it using a keyword argument to the converter load function.

Example -

# Building a Qiskit Circuit
qc = qk.QuantumCircuit(2, 2)
qc.h(0)
#qc.measure(0, 0)
qc.rz(0.543, [0])
qc.cx(0, 1)
qc.measure_all()

# Using the `load` functionality in PL
with qml.tape.OperationRecorder() as recorder:
    load(qc, measurements=None)()

>>> recorder.items()
((Hadamard(wires=[0]), {}),
 (measure(wires=[0]), {}),
 (RZ(0.543, wires=[0]), {}),
 (CNOT(wires=[0, 1]), {}),
 (Barrier(wires=[]), {}),
 (measure(wires=[0]), {}),
 (measure(wires=[1]), {}))

# Override it using the `keyword` argument
measurements = [qml.expval(qml.PauliZ(0)), qml.vn_entropy([0])]
with qml.tape.operation_recorder.AnnotatedQueue() as queue:
    load(qc, measurements=measurements)()
>>> queue
AnnotatedQueue([(Hadamard(wires=[0]), {}),
                (measure(wires=[0]), {}),
                (RZ(0.543, wires=[0]), {}),
                (CNOT(wires=[0, 1]), {}),
                (Barrier(wires=[]), {}),
                (expval(PauliZ(wires=[0])), {}),
                (vnentropy(wires=[0]), {})])

[obliviateandsurrender]

[sc-56072]

[lillian542]

Thanks @obliviateandsurrender ! A couple of comments/suggestions, see what you think :)

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

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[lillian542]

Thanks @obliviateandsurrender! Looks good to me :)

[albi3ro]

changelog?