Add phet-io state handling for the classical and quantum coins

[jbphet]

Setting and conveying state for classical and quantum coins is not yet working, and it's time to add it. This issue will track that work.

[jbphet]

This functionality has been added and appears to be working correctly at this point, though there hasn't been a ton of testing on it. It supports the differences between classical and quantum systems the way that was discussed in the design meetings. Briefly, this was that when a classical system is prepared but hidden and state is set, making an observation will yield the same results in both the upstream and downstream sims. When a quantum system is prepared, the states are not determined until the actual observation is made.

The state setting behavior is working in this dev version in case we ever need to reference it: https://phet-dev.colorado.edu/html/quantum-measurement/1.0.0-dev.6/phet-io/

Closing.

[phet-dev]

Reopening because there is a TODO marked for this issue.

[jbphet]

This was automatically reopened because of a TODO that I'd added related to having to use "as never" type directives. I guess I'll leave it open and look at this more deeply at some point in the future if the problem still exists.