Add Neutron Subnet Pool support in the UI
Since the Kilo release, OpenStack Neutron has supported the concept of "[Subnet Pools|https://docs.openstack.org/newton/networking-guide/config-subnet-pools.html]" which provide a way for users / administrators to define pools of available address space which may then be consumed during the subnet creation process to automatically obtain a non-overlapping subnet allocation (from the requested pool). In short, from a user perspective they help ease the burden of obtaining subnet allocation while ensuring uniqueness (within a given pool).
This feature is beneficial to non-network savvy users, CI/CD & automation use-cases, and service provider (IAAS-5331) use-cases.
This extension is supported in our product today via the API / CLI, and only requires UI work to expose in a more user friendly manner.