Add status panel extensions

[alexymantha]

Summary

Add a new status panel extension hook to customize the status panel.

Motivation

Mentionned in #14463, it would be nice to be able to extend the status panel of an application to display extra information on the application's status. Here is an example of what it would look like for the progressive sync feature:

Similar to optional status such as the sync windows notification.

Proposal

Add a new type of extension in:

argo-cd/ui/src/app/shared/services/extensions-service.ts

Line 4 in 9d48b7a

import {Application, ApplicationTree, State} from '../models';

The Application should be passed to the extensions

Very similar to other types of extension.