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/test/test_dependency_resolver.py

@@ -1,7 +1,7 @@
-from toposort import CircularDependencyError
 import pytest
 
 from awxkit.utils import filter_by_class
+from awxkit.utils.toposort import CircularDependencyError
 from awxkit.api.mixins import has_create