Add load method for apps to bootstrap their panels

Signed-off-by: Julius Härtl <jus@bitgrid.net>

Author: juliusknorr

lib/private/Dashboard/Manager.php

@@ -62,6 +62,7 @@ public function loadLazyPanels(): void {
 			try {
 				/** @var IPanel $panel */
 				$panel = $this->serverContainer->query($class);
+				$panel->load();
 			} catch (QueryException $e) {
 				/*
 				 * There is a circular dependency between the logger and the registry, so

lib/public/Dashboard/IPanel.php

@@ -32,32 +32,37 @@
 interface IPanel {
 
 	/**
-	 * @return string
+	 * @return string Unique id that identifies the panel, e.g. the app id
 	 * @since 20.0.0
 	 */
 	public function getId(): string;
 
 	/**
-	 * @return string
+	 * @return string User facing title of the panel
 	 * @since 20.0.0
 	 */
 	public function getTitle(): string;
 
 	/**
-	 * @return int
+	 * @return int Initial order for panel sorting
 	 * @since 20.0.0
 	 */
 	public function getOrder(): int;
 
 	/**
-	 * @return string
+	 * @return string css class that displays an icon next to the panel title
 	 * @since 20.0.0
 	 */
 	public function getIconClass(): string;
 
 	/**
-	 * @return string The absolute url to the apps own view
+	 * @return string|null The absolute url to the apps own view
 	 * @since 20.0.0
 	 */
-	public function getUrl(): string;
+	public function getUrl(): ?string;
+
+	/**
+	 * Execute panel bootstrap code like loading scripts and providing initial state
+	 */
+	public function load(): void;
 }