[WIP]- New Azure SQL Managed resources

[PriyankaRanganath]

This PR is for new resource configurations:

1) azurerm_mssql_managed_instance
2) azurerm_mssql_managed_instance_admin
3) azurerm_mssql_managed_instance_key
4) azurerm_mssql_managed_instance_encryption_protector
5) azurerm_mssql_managed_database

[mbfrahry]

Hey @PriyankaRanganath, as this is stuck on #1747, I'm going to close this down until the service issues are resolved to a point where we can manage SQL Managed Instance in Terraform.

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. If you feel I made an error 🤖 🙉 , please reach out to my human friends 👉 hashibot-feedback@hashicorp.com. Thanks!