Add behaviour to configure action (extensions)

- Put extension configure view in dir_ext/configure.phtml
- Handle POST action in Extension->handleConfigureAction() method

See https://github.com/FreshRSS/FreshRSS/issues/252

lib/Minz/Extension.php

@@ -86,6 +86,27 @@ class Minz_Extension {
 		return $this->is_enabled;
 	}
 
+	/**
+	 * Return the content of the configure view for the current extension.
+	 *
+	 * @return the html content from ext_dir/configure.phtml, false if it does
+	 *         not exist.
+	 */
+	public function getConfigureView() {
+		$filename = $this->path . '/configure.phtml';
+		if (!file_exists($filename)) {
+			return false;
+		}
+		return @file_get_contents($filename);
+	}
+
+	/**
+	 * Handle the configure POST action.
+	 *
+	 * It must be redefined by child classes.
+	 */
+	public function handleConfigureAction() {}
+
 	/**
 	 * Getters and setters.
 	 */