Add unshareAll() function to Share API

lib/public/share.php

@@ -326,6 +326,20 @@ class Share {
 		return false;
 	}
 
+	/**
+	* @brief Unshare an item from all users, groups, and remove all links
+	* @param string Item type
+	* @param string Item source
+	* @return Returns true on success or false on failure
+	*/
+	public static function unshareAll($itemType, $itemSource) {
+		if ($item = self::getItemShared($itemType, $itemSource)) {
+			self::delete($item['id']);
+			return true;
+		}
+		return false;
+	}
+
 	/**
 	* @brief Unshare an item shared with the current user
 	* @param string Item type