Add a configurable status message banner

[omkar-ethz]

Description

This PR adds a status message banner that can be shown based on values in environment.ts, statusMessage and statusCode which can be one of INFO | WARN | NONE. If statusCode/statusMessage is ommited, no banner is shown hence preserving original behavior.

Motivation

During outages, it is useful to show a status message banner on top of the landing page. E.g. statusCode = WARN:

Or to update the users that the issue has been fixed (i.e. statusCode = INFO):

Fixes:

• none

Changes:

• added a status-banner component, that's in its own NgModule
• Import it in app-component, and trigger visibility based on statusCode env variable.

Tests included/Docs Updated?

• Included for each change/fix?
• Passing? (Merge will not be approved unless this is checked)
• Docs updated?
• New packages used/requires npm install? - no new packages added

Extra Information/Screenshots