ooiion-1374 Platform agent must manage port power for child devices: add agent and driver code

Add code to agent and driver to process the port info objects, check recursion on go_active and control the port power. Skip some code and tests that deal with platform agent NetworkDefinition as this structure needs to be brought into alignment (see ooiion-1495).

@jamie-cyber1 please review
@edwardhunter please review
@mmeisinger please review
@crueda please review