Port changes to d8s dates to other libraries

[fhightower]

Files that need to be changed: (see https://github.com/democritus-project/democritus-dates/compare/2021.02.11...main)

• [x] Add conftest.py
  • [x] Make sure democritus_file_system in requirements_dev.txt
  • [x] Make sure democritus_strings in requirements_dev.txt
• [x] Add conftest.py to .coveragerc
• [x] Update all files in .github/workflows/
• [x] Add Dockerfile
• [x] Remove .travis.yml
• [x] Remove Makefile (if any)
• [x] Update Readme - moved to #62
• [x] Add docker-compose.yml
• [x] Add docker directory
• [x] Add mypy.ini
• [x] Update pyproject.toml
• [x] Update requirements_dev.txt
• [x] Update setup.cfg
• [x] Remove Pipfile and Pipfile.lock

Fixing this issue will fix:

• 28

• 39

• 49

[fhightower]

Procedure:

• Write functions to make these changes
• Create docker container to run the functions in
  • Should mount git config and ssh-key (experiment with how this can be done)
• Run functions on each dir and add/commit/push changes on a branch and then create PR

This ^ system should be created in such a way that it is easy to use in the future.