Add announcement banner component

[spwoodcock]

• Discussed in our team meeting. We don't have a great way to communicate updates, downtime, announcements etc to users (slack is ok, but only has a small reach / audience).

• Here is an example that TM has:

  

• We need a way to update the announcement message, without requiring modifications to code / re-deployments.

• The simplest approach IMO would be loading content from a /public/announcement.json at page load, and if content is present, display the announcement banner.

• This could go in the main header, but it could get a little cluttered (for UI + the code logic). I'm thinking perhaps we make it a separate component?

Note

Adding a simple file like an announcement.json means this can be easily modified by editing the content in S3.

An alternative is to add an endpoint, with database records, but this is a bit more heavyweight and needs modification to the backend of repos too, when it would be preferred to keep this scoped to frontend only.

Important

Where is the best place to add the component? Above the header, as a dismissable toast / popup? Other ideas?

[linear]

TECH-1159