[management] Add option to disable default all-to-all policy (#3970)

This PR introduces a new configuration option `DisableDefaultPolicy` that prevents the creation of the default all-to-all policy when new accounts are created. This is useful for automation scenarios where explicit policies are preferred.
### Key Changes:
- Added DisableDefaultPolicy flag to the management server config
- Modified account creation logic to respect this flag
- Updated all test cases to explicitly pass the flag (defaulting to false to maintain backward compatibility)
- Propagated the flag through the account manager initialization chain

### Testing:

- Verified default behavior remains unchanged when flag is false
- Confirmed no default policy is created when flag is true
- All existing tests pass with the new parameter

infrastructure_files/base.setup.env

@@ -15,6 +15,7 @@ NETBIRD_MGMT_API_CERT_KEY_FILE="/etc/letsencrypt/live/$NETBIRD_LETSENCRYPT_DOMAI
 NETBIRD_MGMT_SINGLE_ACCOUNT_MODE_DOMAIN=$NETBIRD_DOMAIN
 NETBIRD_MGMT_DNS_DOMAIN=${NETBIRD_MGMT_DNS_DOMAIN:-netbird.selfhosted}
 NETBIRD_MGMT_IDP_SIGNKEY_REFRESH=${NETBIRD_MGMT_IDP_SIGNKEY_REFRESH:-false}
+NETBIRD_MGMT_DISABLE_DEFAULT_POLICY=${NETBIRD_MGMT_DISABLE_DEFAULT_POLICY:-false}
 
 # Signal
 NETBIRD_SIGNAL_PROTOCOL="http"
@@ -139,3 +140,4 @@ export NETBIRD_RELAY_PORT
 export NETBIRD_RELAY_ENDPOINT
 export NETBIRD_RELAY_AUTH_SECRET
 export NETBIRD_RELAY_TAG
+export NETBIRD_MGMT_DISABLE_DEFAULT_POLICY

infrastructure_files/management.json.tmpl

@@ -38,6 +38,7 @@
              "0.0.0.0/0"
         ]
     },
+    "DisableDefaultPolicy": $NETBIRD_MGMT_DISABLE_DEFAULT_POLICY,
     "Datadir": "",
     "DataStoreEncryptionKey": "$NETBIRD_DATASTORE_ENC_KEY",
     "StoreConfig": {

infrastructure_files/setup.env.example

@@ -92,7 +92,8 @@ NETBIRD_LETSENCRYPT_EMAIL=""
 NETBIRD_DISABLE_ANONYMOUS_METRICS=false
 # DNS DOMAIN configures the domain name used for peer resolution. By default it is netbird.selfhosted
 NETBIRD_MGMT_DNS_DOMAIN=netbird.selfhosted
-
+# Disable default all-to-all policy for new accounts
+NETBIRD_MGMT_DISABLE_DEFAULT_POLICY=false
 # -------------------------------------------
 # Relay settings
 # -------------------------------------------

infrastructure_files/tests/setup.env

@@ -29,3 +29,4 @@ NETBIRD_TURN_EXTERNAL_IP=1.2.3.4
 NETBIRD_RELAY_PORT=33445
 NETBIRD_AUTH_PKCE_DISABLE_PROMPT_LOGIN=true
 NETBIRD_AUTH_PKCE_LOGIN_FLAG=0
+NETBIRD_MGMT_DISABLE_DEFAULT_POLICY=$CI_NETBIRD_MGMT_DISABLE_DEFAULT_POLICY