Additional port-related RBAC tests

Adds extra port-related RBAC tests to ``test_ports_rbac`` in the
network module, providing coverage for the following policy
actions:
    * create_port:device_owner
    * create_port:port_security_enabled
    * create_port:binding:profile
    * update_port:device_owner

Adds ``test.requires_ext`` above tests that require the ``binding``
extension (because it provides extra functionality
not accessible if disabled [0]).

[0] https://developer.openstack.org/api-ref/networking/v2/#ports

Change-Id: I42d59a2c2d088159d168d3067a133d32ac7f1c00
2 files changed