Updated all links to use https://www.authelia.com/docs/.
Removed all comment sections from documented configuration on the documentation site and replaced them with their own sections.
Made all documentation inside config.template.yml double hashes, and made all commented configuration sections single quoted.
Added .yamllint.yaml to express our desired YAML styles.
Added a style guide.
Refactored many documentation areas to be 120 char widths where possible. It's by no means exhaustive but is a large start.
Added a statelessness guide for the pending Kubernetes chart introduction.
Added labels to configuration documentation and made many areas uniform.
* [FEATURE] File Secret Loading
* add a validator for secrets
* run the secrets validator before the main config validator
* only allow a secret to be defined in one of: config, env, file env
* remove LF if found in file
* update configuration before main config validation
* fix unit tests
* implement secret testing
* refactor the secrets validator
* make check os agnostic
* update docs
* add warning when user attempts to use ENV instead of ENV file
* discourage ENV in docs
* update config template
* oxford comma
* apply suggestions from code review
* rename Validate to ValidateConfiguration
* add k8s example
* add deprecation notice in docs and warning
* style changes
