create sample for port assignment by_port, by_tag, by_id

[mgheorghe]

many of the samples are loading a config.
We need more samples showing how you can use the API to create stuff.

To start with, it will be good to have 3 samples showing how ports can be assigned by each type (by_id, by_port, by_tag). Somehow by_id I was able to do it for a VM, but i never been able to figure out how to assign an APS compute node.