Add additional resource types to variable validaiton

[matt-FFFFFF]

Overview/Summary

Related to #348

Adds advanced setting capability for new resource types released in v2.0.0

• azurerm_private_dns_zone
• azurerm_private_dns_zone_virtual_network_link
• azurerm_firewall_policy
• azurerm_virtual_wan
• azurerm_virtual_hub
• azurerm_express_route_gateway
• azurerm_vpn_gateway
• azurerm_virtual_hub_connection

This PR fixes/adds/changes/removes

1. Adds additional resource types to the connectivity sub-module's custom_settings_by_resource_type variable

Testing Evidence

See registration_enabled = true in this virtual network link:

Created with the below configuration:

advanced = {
  custom_settings_by_resource_type = {
    azurerm_private_dns_zone_virtual_network_link = {
      connectivity = {
        "c953b194-7fa9-439e-9535-49003de2bf00-dc5e2d66-75bc-588d-8a99-28bc142e50a8" = {
          "mylocal.local" = {
            registration_enabled = true
          }
        }
      }
    }
  }
}

As part of this Pull Request I have

• Checked for duplicate Pull Requests
• Associated it with relevant issues, for tracking and closure.
• Ensured my code/branch is up-to-date with the latest changes in the main branch
• Performed testing and provided evidence.
• Updated relevant and associated documentation.
• Updated the "What's New?" wiki page (located in the Enterprise-Scale repo in the directory: /docs/wiki/whats-new.md)

[matt-FFFFFF]

/azp run unit

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[krowlandson]

🚀