add BackupModeSelector.js

www/manager/form/BackupModeSelector.js

+Ext.define('PVE.form.BackupModeSelector', {
+    extend: 'PVE.form.KVComboBox',
+    alias: ['widget.pveBackupModeSelector'],
+  
+    initComponent: function() {
+	var me = this;
+
+	me.data = [
+	    ['snapshot', 'Snapshot'],
+	    ['suspend', 'Suspend'],
+	    ['stop', 'Stop']
+	];
+
+	me.callParent();
+    }
+});