feat: boundary nodes: add caffeine domain polling (dfinity#3686)

Author: blind-oracle

ic-os/components/boundary-guestos/opt/ic/bin/setup-ic-gateway.sh

@@ -133,6 +133,7 @@ POLICY_PRE_ISOLATION_CANISTERS="${RUN_DIR}/pre_isolation_canisters.txt"
 POLICY_DENYLIST_ALLOWLIST="${RUN_DIR}/allowlist.txt"
 POLICY_DENYLIST_SEED="${RUN_DIR}/denylist.json"
 DOMAIN_CANISTER_ALIAS="identity:rdmx6-jaaaa-aaaaa-aaadq-cai,nns:qoctq-giaaa-aaaaa-aaaea-cai"
+DOMAIN_CUSTOM_PROVIDER="https://boundary.caffeine.ai/subdomains,https://beta.boundary.caffeine.ai/subdomains"
 GEOIP_DB="${RUN_DIR}/GeoLite2-Country.mmdb"
 IC_URL="http://127.0.0.1:9000"
 IC_ROOT_KEY="${ROOT_KEY}"