Feature: UrBackup Widget (#1735)

* Add initial UrBackup widget with counts of ok, errored, and out-of date clients

* Add configurable number of days since last backup before a client is considered out-of-date

* Don't count a lack of recent (or error free) image backup if image backup isn't supported.

* Add support for reporting total disk usage

* add support for "fields" from services.yaml

* fix field filtering, syntax

* Consolidate urbackup code, syntax changes

* Revert pnpm changes

* re-add urbackup-server-api

---------

Co-authored-by: shamoon <4887959+shamoon@users.noreply.github.com>

src/widgets/urbackup/widget.js

@@ -0,0 +1,7 @@
+import urbackupProxyHandler from "./proxy";
+
+const widget = {
+  proxyHandler: urbackupProxyHandler,
+};
+
+export default widget;