Add email suffix support to OpenShift connector

[joyrex2001]

Overview

This PR adds an optional emailSuffix configuration option to the OpenShift connector, similar to the LDAP connector emailSuffix configuration option.

What this PR does / why we need it

The email claim contains the username which might not be a valid email address. This breaks integrations which require a valid email address. By adding the emailSuffix configuration option, the connector can be used in these scenarios as well.

Special notes for your reviewer

There are two unittests that check the email claim; one has been adjusted to include the emailSuffix.