Continued review of #2169

- Removed uneeded custom refresh or logout actions for OIDC.
- Restructured how the services and guards are setup for external auth
  systems. SAML2 and OIDC now directly share a lot more logic.
- Renamed any OpenId references to OIDC or OpenIdConnect
- Removed non-required CSRF excemption for OIDC

Not tested, Come to roadblock due to lack of PHP8 support in upstream
dependancies. Certificate was deemed to be non-valid on every test
attempt due to changes in PHP8.

app/Exceptions/OpenIdConnectException.php

@@ -0,0 +1,6 @@
+<?php namespace BookStack\Exceptions;
+
+class OpenIdConnectException extends NotifyException
+{
+
+}

app/Exceptions/OpenIdException.php

@@ -1,6 +0,0 @@
-<?php namespace BookStack\Exceptions;
-
-class OpenIdException extends NotifyException
-{
-
-}