Allow setting the application package and storePath used by the
config. Since the `programs.password-store` Home Manager module sets
config values via global environment variables, the default behavior
of the module should continue to behave as before for the user.
Additionally,
- Adds a few tests.
- Use "escapeShellArg" function call to the path parameter call to
ensure paths with spaces work.
- Allow not setting storePath, which will cause `pass_secret_service`
to default to using `~/.password-store`.
- If `pass-secret-service` is enabled, set its store path to default
to the one defined in our password-store environment settings.
- Add myself (houstdav000) as maintainer.
