mgr/dashboard: add telemetry activation notification

mgr/dashboard: add telemetry activation notification

The commit adds 2 different parts to show the
Telemetry activation notification in the dashboard:

1. The Telemetry activation notification component
   itself. It contains the definition of the
   notification panel.
2. The Telemetry notification service. The service
   is needed to be able to show/hide the
   notification from:
   * the component itself (e.g. when clicking the
     button button)
   * the Telemetry configuration component (when
     enabling/disabling Telemetry)
   * the navigation component (to set the css-
     classes accordingly)

Fixes: https://tracker.ceph.com/issues/45464
Signed-off-by: Tatjana Dehler <tdehler@suse.com>