This adds the following:
- A detect-secrets dependency and a related script
(`script/detect_secrets`) to find and alert developers to secrets
added to the code. By default, the script will search staged and new,
unstaged files. It can optionally search only staged files.
- A whitelist, `.secrets.baseline`, that tracks instances of secrets or
false positives already in the repo.
- Modifies `script/test` to detect secrets as part of the test suite.
- Updates to the README regarding the use of detect-secrets.
Moving virtual environments between systems is problematic... and
unnecessary when creating container images. These modifications allow
the ability to install app dependencies into the system python, and use
that instead of a virtual environment.