enhancement: Make firewall variables and routing intent optional when not used.

[stimmerman]

• Make firewall variables optional when not deploying a firewall
• Updated the SKU validation for the firewall (https://learn.microsoft.com/en-us/cli/azure/network/firewall?view=azure-cli-latest#az-network-firewall-create)
• Make routing intent optional to configure (on by default)
• 1 checkov fix, 1 suppression with comment.

Our use case that lead to this PR was:

• 2 vHubs, one with a firewall, one without.
• Routing intent disabled in both vHub's

The code used to call the module:

module "vwan" {
  source = "/Users/stimmerman/src/schubergphilis/terraform-azure-mcaf-vwan"

  create_new_resource_group = true
  resource_group_name       = module.naming_gwc["vwan"].naming.management_governance.resource_groups
  virtual_wan = {
    name                           = module.naming_gwc["vwan"].naming.networking.virtual_wan
    allow_branch_to_branch_traffic = true
  }

  virtual_hubs = {
    gwc = {
      address_prefix        = "10.124.1.0/24"
      enable_routing_intent = false
      firewall_deploy       = false
      location              = var.location_gwc
      virtual_hub_name      = module.naming_gwc["vwan"].naming.networking.virtual_hub
    }
    weu = {
      address_prefix                    = "10.124.3.0/24"
      enable_routing_intent             = false
      firewall_classic_ip_config        = true
      firewall_dns_servers              = ["8.8.8.8"]
      firewall_intrusion_detection_mode = "Off"
      firewall_name                     = module.naming_weu["vwan"].naming.networking.azure_firewall
      firewall_policy_name              = module.naming_weu["vwan"].naming.networking.azure_firewall_policy
      firewall_proxy_enabled            = true
      firewall_public_ip_count          = 1
      firewall_sku_tier                 = "Standard"
      firewall_threat_intelligence_mode = "Off"
      firewall_zones                    = ["1", "2", "3"]
      location                          = var.location_weu
      virtual_hub_name                  = module.naming_weu["vwan"].naming.networking.virtual_hub
    }
  }
  location = var.location_gwc
  tags     = local.tags
}

[github-actions]

Terraform Format and Style 🖌 success

Terraform Initialization ⚙️ ``

Terraform Lint 📖 success

Terraform Validation 🤖 success

Validation Output

Success! The configuration is valid.

[Blankf]

Approved and tested with classic and new firewall option, did not see any changes from the previous one.