Use code from AdvNetworking for MS SQL Cluster IP validation.

Use code borrowed from murano-conductor for generation of subnets
against which both MS SQL Cluster IPs should be validated (they should
belong to that subnet). Old validation of static IPs is no longer
sufficient because CIDR's are generated by murano-conductor during
deployment.

Valid subnet, once generated in dashboard for validation purposes, is
stored in murano-api environment for later use by murano-conductor
(DRY). So this commit comes in a team with 2 following commits:
https://review.openstack.org/#/c/59982/ and
https://review.openstack.org/#/c/59983/

Change-Id: I02c1b1905dd15535f807bcbc49b4f8fc2ad435d7
Merge "Use code from AdvNetworking for MS SQL Cluster IP validation."