Use file presence to enable OIDC plugin

Add ability to activate the OIDC plugin by creating an empty file called
'activate-oidc-plugin' in the AtoM root dir. If this file is present,
the OIDC plugin will be enabled.

Fix primary provider name in OIDC plugin app.yml files.

config/ProjectConfiguration.class.php

@@ -48,6 +48,12 @@ public function setup()
             'sfPluginAdminPlugin',
         ];
 
+        // Check if the OIDC plugin should be enabled.
+        $filePath = 'activate-oidc-plugin';
+        if (file_exists($filePath) && filesize($filePath) === 0) {
+            $plugins[] = 'arOidcPlugin';
+        }
+
         $this->enablePlugins($plugins);
 
         $this->dispatcher->connect(

docker/etc/oidc/arOidcPlugin/config/app.yml

@@ -64,7 +64,7 @@ all:
           - 'roles'
         user_matching_source: 'oidc-email'
         auto_create_atom_user: true
-    primary_provider_name: primary
+    primary_provider_name: demo
     provider_query_param_name: secondary
     redirect_url: 'http://127.0.0.1:63001/index.php/oidc/login'
     logout_redirect_url: 'http://127.0.0.1:63001'

test/etc/oidc/arOidcPlugin/config/app.yml

@@ -64,7 +64,7 @@ all:
           - 'roles'
         user_matching_source: 'oidc-email'
         auto_create_atom_user: true
-    primary_provider_name: primary
+    primary_provider_name: demo
     provider_query_param_name: secondary
     redirect_url: 'http://localhost/index.php/oidc/login'
     logout_redirect_url: 'http://127.0.0.1'