Split Automate Serializer into own repo

[BenGalewsky]

Move the serializer service into its own repo, independent of the funcx-web repo

Acceptance Criteria

1. funcx-serializer repo in the funkx organization
2. Source code is in a funcx module subdirectory
3. At least one unit test in a test subdirectory
4. Dockerfile at the top level of the directory
5. Flask service runs without TLS termination inside a uWSGI container server
6. Dockerfile entry point starts the server
7. Flask app.config read from mounted volume
8. Flake8 linter configured and runs cleanly
9. GitHub actions to run tests, flake8, and publish docker image to dockerHub. Built image is tagged with the branch name

Assumptions

1. Flake8 lint doesn't require heroic code cleanup efforts. Use enough exceptions to ignore all but the grossest violations.

[BenGalewsky]

Won't fix