sap_vm_provision: Azure compatibility update and fixes

[marcelmamula]

Scope:

1. Updated hardcoded ssh-rsa to ssh- to allow ssh-ed25519 support
2. Added second attempt for IAM Role creation to cover for bug New-AzureRmRoleDefinition - Name Already Exists Azure/azure-powershell#4365 (comment)
3. Added retry loop to tasks that are fired too early, like gathering facts on newly built machine.
4. Fixed typos in AZ Load balancer loop vars
5. Updated Azure governance readme with detailed breakdown of Authentication actions, to offer more secure setup compared to privileged Contributor.
6. Added os_register task to Azure for BYOS registration.
7. Fixed loadbalancer STR<>INT conflicting code

@sean-freeman I am creating this PR now so you are aware of changes, but I will continue with more testing on Azure in coming weeks.

[sean-freeman]

Performed unit test, lgtm 👍