Move OPENSHIFT_ROUTE_PLUGIN_LOCATION to controllers pkg

[jgwest]

What does this PR do / why we need it:

• Move OPENSHIFT_ROUTE_PLUGIN_LOCATION constant to the controllers package, so that it can be consumed downstream.

Have you updated the necessary documentation?

• [ ] Documentation update is required by this PR, and has been updated.

Which issue(s) this PR fixes: N/A

How to test changes / Special notes to the reviewer: