AuthService configuration issues should not be ignored

[n1koo]

Please describe your use case / problem.
If there is a configured AuthService that has a config issue (eg. missing value), Ambassador should die, not just ignore the specification.

Ignoring it means you will rather open the door and than lock if the lock is broken.

For example people hitting: #1058 would see this behaviour of opening their service to the world.

Describe the solution you'd like
If there is a config problem with the AuthService its better to stop processing and panic.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[n1koo]

This is still valid I think?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.