* better oauth provider loading
* add auth frontend
* add configs for all default providers
* add more default providers
* add env variables to enable oauth providers
* small refactor to link/ unlink routes
* add oauth tab to (admin) profile
* use redirects instead of exceptions
* add notification if no oauth user is found
* use import in config
* remove whmcs provider
* replace hardcoded links with `route`
* redirect to account page on unlink
* remove unnecessary controller and handle linking/ unlinking in action
* only show oauth tab if at least one oauth provider is enabled