simplify awxkit dependencies

- remove flake8 as an install requirements (it's only used for tests)
- vendor toposort, which is Apache 2.0 licensed (and very small)
- change websocket-client to a setuptools optional dependency, which you
  can install via:

  pip install "./awxkit[websockets]"

- add `jq` and `tabulate` under an additional optional setuptools
  dependency:

  pip install "./awxkit[formatting]"

- remove `cryptography`, which is only used for random RSA generation
  (unused by the CLI)

awxkit/tox.ini

@@ -12,6 +12,7 @@ passenv = TRAVIS TRAVIS_JOB_ID TRAVIS_BRANCH
 setenv =
     PYTHONPATH = {toxinidir}:{env:PYTHONPATH:}:.
 deps =
+    websocket-client
     coverage
     pytest
     pytest-mock