Restore support for simulation

[alecandido]

Current routines are tuned to work with a Platform, that is ending up in many places.

There is no doubt that Qibolab is the main target of Qibocal, and to move faster I'd accept to support only that for a while.
That's why I imposed the existence of a Platform in #909.

However, running circuits routines in simulation, especially with a specified noise model (but sometimes even noiseless, for debugging) could be very useful.
The proposed way to recover this feature is to wrap a Qibo backend in a qibocal.SimulationBackend, which will hold a qibocal.Platform in the same way as the qibolab.QibolabBackend (and it will respect the qibolab.Platform interface - at least the part used within Qibocal, which we could define somewhere).

This will allow applying all the routines on a simulation backend, and fail if and only if pulses are received.

[alecandido]

Instead of a platform, we could make a Qibocal backend wrapper.

This object will contain the Qibo backend for simulation, and execute circuits, rejecting pulses (but implementing the interface), while for Qibolab will contain (platform, compiler, transpiler), and it will execute pulses (just passing the call to the platform) and circuits (by transpiling, compiling, and eventually passing the call to the platform).

At least, there will be a single object around. And, hopefully, we won't need to access the platform that often (in the future, now need)