Saving & loading experiments

[thopkins32]

It could be useful to save and load the data from previous experiments prior to continuing optimization.

A use case here could be:

• User runs an experiment with Blop and saves the data to a file
• User changes the physical characteristics of the beamline to test a new device
• User runs a new experiment with Blop
• User changes the beamline back to its original state
• User loads the older experiment data to continue optimizing the beamline

We could possibly introduce some structure here to include metadata (maybe RunEngine metadata?).

There is also an option to have a SQL database, but this can be left for future work.

See https://ax.dev/docs/recipes/experiment-to-json