Add i18n support

Make the "Running on.." string translatable and copy the extraction and
conversion of JSX and PO files from Cockpit.

po/po.empty.js

@@ -0,0 +1,14 @@
+(function (root, data) {
+    var loaded, module;
+
+    /* Load into Cockpit locale */
+    if (typeof cockpit === 'object') {
+        cockpit.locale(data)
+        loaded = true;
+    }
+
+    if (!loaded)
+        root.po = data;
+
+/* The syntax of this line is important  by po2json */
+}(this, {"":{"language":"en"}}));