We frequently receive reports from users who have issues with credentials.
One of the most common cases, besides the mobile app users' uppercasing the first letter, is due to the provisioning through "tplink simple setup" (tss) where the newly provisioned devices do not accept the regular credentials.

This PR adds a new exception that can be caught to display user a more detailed message about what they can do to fix the issue.

This has not been tested yet, so drafting for now.

Fixes #1573