utils: copy over async helpers

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

src/Utils.js

@@ -1037,3 +1037,28 @@ utilities: {
 	me.VlanInterface_match = /(\w+)\.(\d+)/;
     },
 });
+
+Ext.define('Proxmox.Async', {
+    singleton: true,
+
+    // Returns a Promise resolving to the result of an `API2Request`.
+    api2: function(reqOpts) {
+	return new Promise((resolve, reject) => {
+	    delete reqOpts.callback; // not allowed in this api
+	    reqOpts.success = response => resolve(response);
+	    reqOpts.failure = response => {
+		if (response.result && response.result.message) {
+		    reject(response.result.message);
+		} else {
+		    reject("api call failed");
+		}
+	    };
+	    Proxmox.Utils.API2Request(reqOpts);
+	});
+    },
+
+    // Delay for a number of milliseconds.
+    sleep: function(millis) {
+	return new Promise((resolve, _reject) => setTimeout(resolve, millis));
+    },
+});