* Refactor authentication to allow for OpenID Connect
The authentication class has been refactored to separate the `validate` function for the method `create_user_session`. This is needed for the OpenID Connect module to authenticate a user without going through the process of all authentication plugins. Only the function `check_user_cidr` has been rewritten to use a single loop instead of a double-loop.
Due to the fact that create_user_function is public, the $result associative array is checked to ensure the required fields are present and the UUID fields are valid UUIDs. Further checking could be done against the database to ensure the UUIDs exist but this has been suppressed at this time because database queries would be required.
* Database class modified to allow for login banners for OpenID Connect
The database class is responsible for creating the view for login. The OpenID application required banners to be present so that any OpenID Connect authentication mechanism could be used. Each banner displayed has the properties of: name, image, alt, and url. The name is the class name of the authentication plugin. This will match the action in the URL. The image is the image banner used for the login. The alt is the alternate text used for screen readers. Each authenticator is responsible for providing each of the field values.
* Added PHPDocs for the check_cidr function
* Add backwards compatibility for PHP versions below 8
* Remove get_banner_alt
* Update check_cidr to allow cidr array
* Update authentication.php
* Update functions.php
* Update authentication.php
