Sync to include changes for both Protostellar and classic paths

Protostellar efforts were paused for a while due to higher priority tasks. Now that those tasks are complete, the Python SDK PS changes need to be updated to incorporate the changes that have occurred during the pause.

Tasks:

• Update to incorporate changes from CNG that impact the protostellar path (conn string, proto buf updates, exceptions, etc.)
• Changes from the core C++ (and Python SDK bindings) that impact the classic path
  • NOTE: changes coming for C++ 1.0.0-dp.11 are going to be significant so, need to be prepared to incorporate those changes as well
• Merge all local changes to PYCBC-1447 branch in forked repo (provides easier tracking for upcoming merge to mainline)
• Organize tickets to outline work remaining