feat(python): Constructors, iterators, and other utility methods have been added to make working with ResultData, RegisterMap, and others easier.

[MarquessV]

This supports pyQuil#1630 by making it easier to construct and iterate over the result data types.

This does not change the return shape of qpu::api::retrieve_results. The target would be to construct a QpuResultData, but the data we need simply isn't available in that function to build it.

We could alternatively use the Executable struct, which has it's own workflow that already returns QpuResultData, but pyQuil's QAM is already workflow based and it's quite clunky to try and use one in the other.

I think it would be good to reconcile this before a v1.0 release, but this gets us passed the issue for now. In the end, this actually doesn't shove off too much to pyQuil.

TODO:

• Add stubs after API approval
• Figure out if we can better expose types for QPU/QVMResultData.asdict() Took a different approach.

[Shadow53]

A few minor suggestions, but looks good overall

[BatmanAoD]

This looks reasonable to me. I've added lots of questions for my own edification, but I'm not sure any of them indicate a lack of sufficient comments or documentation so much as my own lack of context.