CONSIDER: Application/Banner Alert on Facility Locator

Issue Description

How might we enable a method to incorporate some sort of application banner alert on Facility Locator

Instances where this may be important:

Exceptional national emergency (e.g. COVID before there were individual COVID status)
Service outage - How can we make Veterans aware that community care searches are temporarily unavailable? Because we have the ability to flip off PPMS searches in the event of a bug, we should provide information about the downtime.

[ ] Determine best method for notifying Veterans about temporary search disruptions

[ ] What will be created or happen as a result of this story?

How to configure this issue
[ ] Attached to a Milestone (when will this be completed?)
[ ] Attached to an Epic (what body of work is this a part of?)
[ ] Labeled with Team (product support, analytics-insights, operations, service-design, tools-be, tools-fe)
[ ] Labeled with Practice Area (backend, frontend, devops, design, research, product, ia, qa, analytics, contact center, research, accessibility, content)
[ ] Labeled with Type (bug, request, discovery, documentation, etc.)