Support schema-based initialization for calibrators

[natestemen]

Once #2586 is closed we can start using the schema do to stuff! First, we should be able to instantiate a new Calibrator object using the schema.

To close this issue we should be able to run the following code block.

qem_experiment = {...}  # something that adheres to the schema

cal = Calibrator.from_schema(qem_experiment)

The code in from_schema should handle when qem_experiment is well defined, and when it is ill-formed, giving the user as helpful an error as possible.

cc @ecarlander @ruheenirodi let me know who I should assign! You'll have to comment on the issue in order to be assigned. Also, are the schemas with parameter sweeps ready to be added here? Should we keep that for a separate issue?

[ruheenirodi]

also commenting for assignment!

[ecarlander]

Commenting to be assigned! The parameter sweeps are currently in the mitiq/schema directory from the other issue (#2586)