neutron: Add unit test from Port

Added tests for port serialization/deserialization

Signed-off-by: Mike Kolesnik <mkolesni@redhat.com>
neutron: Format Subnet class

Signed-off-by: Mike Kolesnik <mkolesni@redhat.com>
neutron: Unify Subnet entity

Unified subnet entity with SubnetForCreate, deprecating the later as
it's no longer necessary.

Signed-off-by: Mike Kolesnik <mkolesni@redhat.com>
neutron: Format Network class

Signed-off-by: Mike Kolesnik <mkolesni@redhat.com>
neutron: Unify Network entity

Unified network entity with NetworkForCreate, deprecating the later as
it's no longer necessary.

Signed-off-by: Mike Kolesnik <mkolesni@redhat.com>