Allow setting socketActivated: true on converted ports

[Yossibh]

When converting a Docker image to ACI, the converted ports are always set to "socketActivated: false".

It would be handy to have a CLI flag to control the socketActivated property on the converted ACI image or have the ability to change something on the input Docker image to hint the tool that this is a SocketActivated port.

This is following a discussion here: https://groups.google.com/forum/#!topic/rkt-dev/WZrAGMOVZrY