V4: Standardize on ExecutionData

[Shadow53]

Pre-Request Checklist

• I am running the latest versions of pyQuil and the Forest SDK
• I checked to make sure that this feature has not already been requested

Issue Description

pyQuil v4 uses qcs_sdk to provide much of its functionality. qcs_sdk provides at two ways to run a program: either through a set of functions submit and retrieve_results, or through an API around an Executable type.

The Executable API allows accessing the original data returned by QPU or QVM as QPUResultData or QVMResultData, respectively, and also provides a way to use a common processed format called RegisterMap.

The method pyQuil uses, however, is the pair of functions, which directly unpack the gRPC response and repack it into a new, separate Python type with less flexibility.

Proposed Solution

I propose either using the Executable API in the QuantumAbstractMachine implementations for QPU and QVM, or at the very least using the ExecutionData/ResultData types when returning execution results.

Additional References

• This seems related to Mcm measurement buffers #1629
• This will probably require some changes in rigetti/qcs-sdk-rust

[MarquessV]

closed via #1631