* [FEATURE] Docker simplification and configuration generation
The Authelia binary now will attempt to generate configuration based on the latest template assuming that the config location specified on startup does not exist. If a file based backend is selected and the backend cannot be found similarly it will generate a `user_database.yml` based a template.
This will allow more seamless bootstrapping of an environment no matter the deployment method.
We have also squashed the Docker volume requirement down to just `/config` thus removing the requirement for `/var/lib/authelia` this is primarily in attempts to simplify the Docker deployment.
Users with the old volume mappings have two options:
1. Change their mappings to conform to `/config`
2. Change the container entrypoint from `authelia --config /config/configuration.yml` to their old mapping
* Adjust paths relative to `/etc/authelia` and simplify to single volume for compose
* Add generation for file backend based user database
* Refactor Docker volumes and paths to /config
* Refactor Docker WORKDIR to /app
* Fix integration tests
* Update BREAKING.md for v4.20.0
* Run go mod tidy
* Fix log_file_path in miscellaneous.md docs
* Generate config and userdb with 0600 permissions
* Fix log_file_path in config.template.yml
* implement SMTP notifier startup check
* check dial, starttls, auth, mail from, rcpt to, reset, and quit
* log the error on failure
* implement mock
* misc optimizations, adjustments, and refactoring
* implement validate_skip config option
* fix comments to end with period
* fix suites that used smtp notifier without a smtp container
* add docs
* add file notifier startup check
* move file mode into const.go
* disable gosec linting on insecureskipverify since it's intended, warned, and discouraged
* minor PR commentary adjustment
* apply suggestions from code review
Co-Authored-By: Amir Zarrinkafsh <nightah@me.com>