* initial work
- adding put_secret_value and list_secret_versions
* Added support for versions in all functions except rotate_secret
* more work
- refactor rotate_secret method
- now, adds a new version of the secret and points default version id to it
- updated implementation coverage readme
- element in list check to fix unit test
- fixed linting errors
- added tests, fixed exception, failing tests still
- secrets_manager/test_server fails when running whole suite,
but not when running that individual test file
* fixed failing test_get_secret_value
* Removed test.py. Fixed condition statement.
* fixed default stages + adding AWSPREVIOUS
* remove old AWSPREVIOUS stages
