chore: add nsg for default subnet (#829)

<!--- Provide a general summary of your changes in the Title above -->

## Description

<!--- Describe your changes in detail -->

Adding a wide open NSG on the default subnet. Should be restricted soon.
Allows us to place resources in it now and add restrictions as we go

## Related Issue(s)

- #{issue number}

## Verification

- [ ] **Your** code builds clean without any errors or warnings
- [ ] Manual testing done (required)
- [ ] Relevant automated test added (if you find this hard, leave it and
we'll help out)

## Documentation

- [ ] Documentation is updated (either in `docs`-directory, Altinnpedia
or a separate linked PR in
[altinn-studio-docs.](https://github.com/Altinn/altinn-studio-docs), if
applicable)

.azure/modules/vnet/main.bicep

@@ -4,6 +4,44 @@ param namePrefix string
 @description('The location where the resources will be deployed')
 param location string
 
+resource defaultNSG 'Microsoft.Network/networkSecurityGroups@2023-11-01' = {
+  name: '${namePrefix}-default-nsg'
+  location: location
+  properties: {
+    securityRules: [
+      // todo: restrict the ports further
+      {
+        name: 'AllowAnyCustomAnyInbound'
+        type: 'Microsoft.Network/networkSecurityGroups/securityRules'
+        properties: {
+          protocol: '*'
+          sourcePortRange: '*'
+          destinationPortRange: '*'
+          sourceAddressPrefix: '*'
+          destinationAddressPrefix: '*'
+          access: 'Allow'
+          priority: 100
+          direction: 'Inbound'
+        }
+      }
+      {
+        name: 'AllowAnyCustomAnyOutbound'
+        type: 'Microsoft.Network/networkSecurityGroups/securityRules'
+        properties: {
+          protocol: '*'
+          sourcePortRange: '*'
+          destinationPortRange: '*'
+          sourceAddressPrefix: '*'
+          destinationAddressPrefix: '*'
+          access: 'Allow'
+          priority: 100
+          direction: 'Outbound'
+        }
+      }
+    ]
+  }
+}
+
 // https://learn.microsoft.com/en-us/azure/container-apps/firewall-integration?tabs=consumption-only
 resource containerAppEnvironmentNSG 'Microsoft.Network/networkSecurityGroups@2023-11-01' = {
   name: '${namePrefix}-container-app-environment-nsg'
@@ -231,6 +269,9 @@ resource virtualNetwork 'Microsoft.Network/virtualNetworks@2023-11-01' = {
         name: 'default'
         properties: {
           addressPrefix: '10.0.0.0/24'
+          networkSecurityGroup: {
+            id: defaultNSG.id
+          }
         }
       }
       {