Add laser power mapping for each mesoscope plane

[dougollerenshaw]

Sam Seid requested some metadata changes in this issue:
https://github.com/AllenNeuralDynamics/aind-scientific-computing/issues/271

One of the is a request to track the laser power for each mesoscope plane in mW. This would require a change to the mesoscope metadata mapper here.

Spinning that off as a subissue for easier tracking.

@dbirman can you confirm that this would require no changes to the metadata schema?

@arielleleon should this change be tied to the schema 2.0 upgrade for the mesoscope metadata mapper?

[arielleleon]

@dougollerenshaw - yes, I think that would be a good idea. Thanks!