add port forwarding to omv.yaml

[goern]

As a section to omv.yaml so that portforwarding could be configured by Oh-My-Vagrant. This will complement vfwd. Something like

forward:
  8443:master:8433
  80:master:8080

would be nice.

[purpleidea]

@goern agreed. Patches welcome :)

[purpleidea]

Bonus points if the values support simple math expressions, so you can do things like:

forward:
    8443+$i:omv$i:80+$i

so that you don't have to add N entries, for count: N
In fact, this could be done with a simplistic string parser (string.endswith+$i) sort of thing...