Host to container networking

TLDR;

Opctl supports using ports statements to bind opctl container ports to opctl node host ports.

Example

1. Start this op:

   name: curl
   run:
     container:
       image: { ref: nginx:alpine }
       ports:
         # bind container port 80 to host port 8080
         80: 8080
2. On the opctl host, open a web browser to localhost:8080.
3. Observe the nginx containers default page is returned.