Add external-ip support for coturn (#1439)

Handles the case when users are running Coturn with peers in the same network, and these peers connect to the relay server via private IP addresses (e.g., Oracle cloud), which causes relay candidates to be allocated using private IP addresses. This causes issues with external peers who can't reach these private addresses.

Use the provided IP address with NETBIRD_TURN_EXTERNAL_IP or discover the address via https://jsonip.com API.

For quick-start guide with Zitadel, we only use the discover method with the external API

.github/workflows/test-infrastructure-files.yml

@@ -87,8 +87,10 @@ jobs:
           CI_NETBIRD_SIGNAL_PORT: 12345
           CI_NETBIRD_STORE_CONFIG_ENGINE: "sqlite"
           CI_NETBIRD_MGMT_IDP_SIGNKEY_REFRESH: false
+          CI_NETBIRD_TURN_EXTERNAL_IP: "1.2.3.4"
 
         run: |
+          set -x
           grep AUTH_CLIENT_ID docker-compose.yml | grep $CI_NETBIRD_AUTH_CLIENT_ID
           grep AUTH_CLIENT_SECRET docker-compose.yml | grep $CI_NETBIRD_AUTH_CLIENT_SECRET
           grep AUTH_AUTHORITY docker-compose.yml | grep $CI_NETBIRD_AUTH_AUTHORITY
@@ -120,6 +122,7 @@ jobs:
           grep -A 10 PKCEAuthorizationFlow management.json | grep -A 10 ProviderConfig | grep TokenEndpoint | grep $CI_NETBIRD_AUTH_TOKEN_ENDPOINT
           grep -A 10 PKCEAuthorizationFlow management.json | grep -A 10 ProviderConfig | grep Scope | grep "$CI_NETBIRD_AUTH_SUPPORTED_SCOPES"
           grep -A 10 PKCEAuthorizationFlow management.json | grep -A 10 ProviderConfig | grep -A 3 RedirectURLs | grep "http://localhost:53000"
+          grep "external-ip" turnserver.conf | grep $CI_NETBIRD_TURN_EXTERNAL_IP
 
       - name: Install modules
         run: go mod tidy
@@ -175,7 +178,10 @@ jobs:
       - name: test management.json file gen
         run: test -f management.json
       - name: test turnserver.conf file gen
-        run: test -f turnserver.conf
+        run: | 
+          set -x
+          test -f turnserver.conf
+          grep external-ip turnserver.conf
       - name: test zitadel.env file gen
         run: test -f zitadel.env
       - name: test dashboard.env file gen