Alert the user to authenticate as necessary

[markcraig]

• When attempting to authenticate with an expired JWT, HDAP responds with HTTP 401 and requests HTTP Basic auth, causing the browser to pop up a dialog prompting for username and password. It would be better to notice the expiration, proactively remove the persisted JWT, and alert the user.
• On HTTP 401 or HTTP 403 responses from HDAP, alert the user.

[markcraig]

Consider https://axios-http.com/docs/handling_errors

[markcraig]

Resolved by https://github.com/markcraig/hdap-demo/pull/3

[markcraig]

Closing this