Rename initCsrfToken to addCsrfToken and move it upwards

Form::addCsrfToken() should be public and fluent to ensure more
flexibility.

refs #5525

library/Icinga/Web/Form.php

@@ -157,6 +157,26 @@ class Form extends Zend_Form
         return $this;
     }
 
+    /**
+     * Add CSRF counter measure field to this form
+     *
+     * @return  self
+     */
+    public function addCsrfToken()
+    {
+        if (false === $this->tokenDisabled && $this->getElement($this->tokenElementName) === null) {
+            $this->addElement(
+                'hidden',
+                $this->tokenElementName,
+                array(
+                    'value' => $this->generateCsrfToken()
+                )
+            );
+        }
+
+        return $this;
+    }
+
     /**
      * Load the default decorators
      *
@@ -184,22 +204,6 @@ class Form extends Zend_Form
         return $this;
     }
 
-    /**
-     * Add CSRF counter measure field to this form
-     */
-    protected function initCsrfToken()
-    {
-        if (false === $this->tokenDisabled && $this->getElement($this->tokenElementName) === null) {
-            $this->addElement(
-                'hidden',
-                $this->tokenElementName,
-                array(
-                    'value' => $this->generateCsrfToken()
-                )
-            );
-        }
-    }
-
     /**
      * Generate a new (seed, token) pair
      *