[DEM-944] fsp vs non-fsp in qiskit

[QFer]

The following general rules are implemented for both Qiskit and ProjectQ (another PR):

• An algorithm without measurements or only measurements at the end (no gates following the measurements) can be executed as full state projection, otherwise it is executed as non-fsp.
• Also in a non-fsp algorithm not more than one different qubits may be measured to a classical bit and a qubit may not be measured to more than one classical bit.
• When a non-fsp algorithm is run the warning as specced in the desired outcome of the ticket DEM-944 should be printed, according to the acceptance criteria. In api there is a method to enable or disable this warning:

show_fsp_warning(self, enable: bool = True)

[coveralls]

Coverage remained the same at 100.0% when pulling 951e6fb2bdce7f37cf6ba6c72d7d44a568129f61 on feature/dem-944/measurement_in_qiskit into a0ccfc6e76c447d495e2aa86fc14de3855c87d76 on dev.

[QFer]

Rebased