Refactor authentication system (#2602)

Make auth configuration available via UI, remove FOSUserBundle and SAML-Bundle dependency

src/Form/Model/Configuration.php

@@ -50,7 +50,7 @@ final class Configuration
      */
     private $constraints = [];
 
-    public function getName(): string
+    public function getName(): ?string
     {
         return $this->name;
     }

src/Form/Model/SystemConfiguration.php

@@ -18,6 +18,7 @@ class SystemConfiguration
     public const SECTION_FORM_CUSTOMER = 'form_customer';
     public const SECTION_FORM_USER = 'form_user';
     public const SECTION_THEME = 'theme';
+    public const SECTION_AUTHENTICATION = 'authentication';
     public const SECTION_CALENDAR = 'calendar';
     public const SECTION_BRANDING = 'branding';
 
@@ -50,6 +51,17 @@ class SystemConfiguration
         return $this->configuration;
     }
 
+    public function getConfigurationByName(string $name): ?Configuration
+    {
+        foreach ($this->configuration as $configuration) {
+            if ($configuration->getName() === $name) {
+                return $configuration;
+            }
+        }
+
+        return null;
+    }
+
     /**
      * @param Configuration[] $configuration
      * @return SystemConfiguration