[WIP] app-ng HTTP API v0

[appleby]

This is a WIP PR intended to address #155 and #39. This also includes the commits from the earlier (abandoned) #146.

So far this is a nearly wholesale import of code from "qvm-app classic" with only light refactorings. The idea is to start with working code, surround it with tests, and refactor to its final form.

Currently working endpoints:

• version
• multishot / qc.run() (trivially satisfied via code import)
• make-persistent-qvm
• persistent-qvm-info
• delete-persistent-qvm
• multishot on a persistent QVM

Still no reconfiguration ability, no noise models. Just simulation-method and number-of-qubits.

For the adventurous early reviewer, most of the new code is in:

• tests/test-rest-api.lisp
• src/handle-request.lisp
• src/api/persistent-qvm.lisp

TODO:

• [x] demo persistence api
• [x] more tests
• [ ] refactor refactor refactor
• [ ] comments/docstrings
• [ ] address outstanding TODOs in source

[appleby]

Closing this in favor of a more principled from-scratch approach, rather than wholesale import & refactor.