Inform user of session expiration

[pieperm]

Is your feature request related to a problem? Please describe.
Currently, users receive no warning about being timed out of their current login session, nor are they prompted to log in again once they are automatically logged out.

Describe the solution you'd like
When the authentication token is about to expire (e.g. 5 minutes beforehand) the user should receive a pop-up on the page that lets the user know they will be automatically timed out. If the user is timed out, they should be taken to a page that tells them they have been timed out, and includes a link back to the login page.

Describe alternatives you've considered
N/A

Additional context
This is related to the implementation of background refresh tokens in # #1717

[mkimberlin]

I believe this need re-addressed due to regression post-change from axios to fetch. This should also address #1557.