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). Subnet is generated for every new environment, but is used only
during MS SQL Cluster IP validation.

This commit comes in a team with 3 following commits:
https://review.openstack.org/#/c/59982/
https://review.openstack.org/#/c/59983/
https://review.openstack.org/#/c/61072/

Change-Id: I24b3c057fe43e9a35a96ddf2c4defd4f64e9b4ea
Merge "Use code from AdvNetworking for MS SQL Cluster IP validation."