Fixes #7643: Expose Puppet CA proxy option.

Exposing the puppet CA proxy option such that a capsule can serve
as a Puppet server but allow puppet agents to be proxied to a central
CA that is typically present on the Katello server itself.
Merge pull request #21 from ehelms/fixes-7643

Fixes #7643: Expose Puppet CA proxy option.
Fixes #7745 - create apache reverse-proxy to parent