sap_vm_provision: allow Private DNS on MS Azure to use Auto Registration

[sean-freeman]

Allow Private DNS on MS Azure to use Auto Registration, append new variable and logic sap_vm_provision_msazure_private_dns_auto_register that would skip the DNS Record entries created for the VM (but still append the DNS Record entries for HA Virtual IP).

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NOTE:

At this time, the code will not be altered to allow no Private DNS to be specified. it remains best practice to:

• use the DNS Zone record (s4hana.myorg.cloud) for the inter-Cloud communications
• use the Corporate DNS Server’s Subzone record (s4hana.myorg.corp) for the internal traffic
• use the Corporate DNS Server’s Subdomain Delegation record (s4hana-webdisp.myorg.com) for the public internet traffic

The sap_vm_provision attempts to keep as much homogeneity as possible for Infrastructure Platforms, and each Cloud Service Provider has a Private DNS in their designs for SAP Landscapes.

[sean-freeman]

Resolved in PR #17 by using a check whether auto registration is enabled, which will skip the DNS Records creation (not the DNS Records for HA)