Remove tunnel services and Auto DevOps settings

What does this Merge Request do?

Removes the auto_devops config setting and tunnel services:

• The QA tunnel is no longer in use, so these settings cannot provide a working GDK.
• The auto_devops setting used a number of special cases when configuring the GDK, so we can reduce complexity by removing it.

#1122 (closed)

Merge Request checklist

• Tests added for new functionality. If not, please raise Issue to follow-up.
• This change is backward compatible. If not, please include steps to communicate to our users.
• [-] Documentation added/updated, if needed. - !1716 (merged)
• gdk doctor test added, if needed.