ui: add help tool to datastore panel

www/Utils.js

@@ -224,6 +224,30 @@ Ext.define('PBS.Utils', {
 	    Proxmox.Utils.format_size(val), Proxmox.Utils.format_size(max)) + ')';
     },
 
+    get_help_tool: function(blockid) {
+
+	let info = Proxmox.Utils.get_help_info(blockid);
+	if (info === undefined) {
+	    info = Proxmox.Utils.get_help_info('pbs_documentation_index');
+	}
+	if (info === undefined) {
+	    throw "get_help_info failed"; // should not happen
+	}
+
+	let docsURI = window.location.origin + info.link;
+	let title = info.title;
+	if (info.subtitle) {
+	    title += ' - ' + info.subtitle;
+	}
+	return {
+	    type: 'help',
+	    tooltip: title,
+	    handler: function() {
+		window.open(docsURI);
+	    }
+        };
+    },
+
     constructor: function() {
 	var me = this;
 

www/datastore/DataStoreList.js

@@ -203,6 +203,8 @@ Ext.define('PBS.datastore.DataStores', {
 	border: false,
     },
 
+    tools: [PBS.Utils.get_help_tool("datastore_intro")],
+
     items: [
 	{
 	    xtype: 'pbsDataStoreList',

www/datastore/Panel.js

@@ -34,6 +34,8 @@ Ext.define('PBS.DataStorePanel', {
 	border: false,
     },
 
+    tools: [PBS.Utils.get_help_tool("datastore_intro")],
+
     items: [
 	{
 	    xtype: 'pbsDataStoreSummary',