remove image methods and property from Sidebar class, fixes #3157

Closes #3157

Merge request studip/studip!2134

lib/classes/sidebar/Sidebar.php

@@ -8,10 +8,6 @@
  */
 class Sidebar extends WidgetContainer
 {
-    /**
-     * Contains an optional image for the container.
-     */
-    protected $image = false;
     protected $title = false;
     protected $context_avatar = null;
 
@@ -23,38 +19,6 @@ class Sidebar extends WidgetContainer
         $this->setTitle();
     }
 
-    /**
-     * Set an image for the sidebar.
-     *
-     * @param String $image The image relative to assets/images
-     * @deprecated since Stud.IP 4.5
-     */
-    public function setImage($image)
-    {
-    }
-
-    /**
-     * Returns the image for the sidebar.
-     *
-     * @return mixed Either the previously set image or false if no image
-     *               has been set.
-     * @deprecated since Stud.IP 4.5
-     */
-    public function getImage()
-    {
-        return $this->image;
-    }
-
-    /**
-     * Removes a previously set image.
-     *
-     * @deprecated since Stud.IP 4.5
-     */
-    public function removeImage()
-    {
-        $this->image = false;
-    }
-
     /**
      * Set a title of the sidebar.
      *