start experimental tape management GUI

You need to set the environment TEST_TAPE_GUI=1 to enable this.
The current GUI is only a placeholder.

www/Makefile

@@ -4,6 +4,13 @@ IMAGES := \
 	images/logo-128.png \
 	images/proxmox_logo.png
 
+TAPE_UI_FILES=
+
+ifdef TEST_TAPE_GUI
+TAPE_UI_FILES=						\
+	TapeManagement.js
+endif
+
 JSSRC=							\
 	Utils.js					\
 	form/UserSelector.js				\
@@ -63,6 +70,7 @@ JSSRC=							\
 	ServerStatus.js					\
 	ServerAdministration.js				\
 	Dashboard.js					\
+	${TAPE_UI_FILES}				\
 	NavigationTree.js				\
 	Application.js					\
 	MainView.js

www/NavigationTree.js

@@ -116,6 +116,19 @@ Ext.define('PBS.view.main.NavigationTree', {
 
 	    let root = view.getStore().getRoot();
 
+	    if (PBS.TapeManagement !== undefined) {
+		if (!root.findChild('id', 'tape_management', false)) {
+		    root.insertChild(3, {
+			text: "Tape Management",
+			iconCls: 'fa fa-gears',
+			id: 'tape_management',
+			path: 'pbsTapeManagement',
+			expanded: true,
+			children: [],
+		    });
+		}
+	    }
+
 	    records.sort((a, b) => a.id.localeCompare(b.id));
 
 	    var list = root.findChild('id', 'datastores', false);

www/TapeManagement.js

@@ -0,0 +1,11 @@
+Ext.define('PBS.TapeManagement', {
+    extend: 'Ext.tab.Panel',
+    alias: 'widget.pbsTapeManagement',
+
+    title: gettext('Tape Management'),
+
+    border: true,
+    defaults: { border: false },
+
+    html: "Experimental tape management GUI.",
+});