Chore: Group auth docker blocks (#54274)

* Move auth docker images to parent folder

* Add README file for auth parent folder

* Add grafana-authnz-team as code owner

* Update `devenv` docs

devenv/docker/blocks/auth/saml/users.php

@@ -0,0 +1,21 @@
+<?php
+$config = array(
+    'admin' => array(
+        'core:AdminPassword',
+    ),
+    'example-userpass' => array(
+        'exampleauth:UserPass',
+        'saml-admin:grafana' => array(
+            'groups' => array('admins'),
+            'email' => 'saml-admin@grafana.com',
+        ),
+        'saml-editor:grafana' => array(
+            'groups' => array('editors'),
+            'email' => 'saml-editor@grafana.com',
+        ),
+        'saml-viewer:grafana' => array(
+            'groups' => array(),
+            'email' => 'saml-viewer@grafana.com',
+        ),
+    ),
+);