Introduce a deterministic algorithm for choosing a port for the aggregator server.

[igor-davidyuk]

The workflow will probably be as follows: Director config will feature a new parameter open_ports listing one or more ports. This list will be tracked by the Director-service, which will provide one of the ports to the Aggregator at the start time.

[ladi-pomsar]

Hi,

Thank you for doing this. Motivation behind this is that when one is working on secure system, it is important to open just as much ports as is needed, in a controlled fashion. With aggregator picking "random" port, it is rather problematic to achieve minimalisation of open ports.