Service status notifications

[samuelthomas2774]

Add service status notifications that appear in the main window, similar to the update notifications. Status updates can be fetched from nxapi-auth and other sources, e.g. presence URLs can add status update sources by returning a link header to fetch status updates from.

This can be used to show a banner in the app when Nintendo breaks things.

To do:

• Fetching status updates
• Adding status update sources
• Update nxapi-auth