Enable port forwarding on a given pod and a given debug port

Given a remote debug port, we need to ensure to programmatically enable port forwarding on a pod, return the matching local debug port (named debug).

The local port could be determined as the next available free port, or read from the server adapter's preferences. But that latter case would also require adding some UI to let a user set the local port. That could be done in a later iteration.

If port forwarding is already enabled on the remote pod, then the current local debug port should be returned