Konnect basic auth: fix or remove

[pmalek]

It seems that using basic auth against Konnect is not "the way to go".

This issue tracks the decision and implementation of that decision, whether we should fix it somehow or remove the related functionality, e.g. the CLI flags

      --konnect-email string                       Email address associated with your Konnect account.
      --konnect-password --konnect-password-file   Password associated with your Konnect account, this takes precedence over --konnect-password-file flag.
      --konnect-password-file string               File containing the password to your Konnect account.

, related functionality and tests.