Update Serialization

[marip8]

This PR adds serialization to some of the types defined in rct_optimizations

[marip8]

@schornakj can you review?

[schornakj]

@marip8 Looks good in general, just a few questions.

I would also suggest adding some unit tests to at minimum verify that converting various types to YAML and then back again returns the same original value.

[drchrislewis]

@marip8 @schornakj I made some suggestions, but nothing major. I approved, but did not merge.