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/requirements.txt

@@ -1,8 +1,4 @@
 PyYAML>=5.1
-cryptography
-flake8
 python-dateutil
 requests
 termcolor
-toposort
-websocket-client>=0.54.0