luci-mod-status: improve RDNS resolution workflow

luci-mod-status: improve RDNS resolution workflow

- Add new RPC declarations:
  - callLuciRpcGetNetworkDevices
  - callLuciRpcGetDHCPLeases
- Add ethers_cache for MAC-to-hostname mapping
- Replace object literals with Object.create(null) for caches:
  dns_cache, service_cache
- Make sure 'Disable DNS lookups' shows addresses
- Change lookup_queue from array to Set to simplify processing
- Introduce updateDnsCache(addr, name) helper to update caches and remove
  addresses from queues
- Update service lookup to match uppercase cache keys
- Rework address resolution workflow as async/await
  1. DHCP leases
  2. Reverse DNS via callNetworkRrdnsLookup
  3. Host hints / MAC-to-host mapping
  4. Network devices / MAC cache
- Re-write pollData() as async
- Update ACL JSON to grant luci-mod-status access to luci-rpc
  methods: getHostHints, getNetworkDevices, getDHCPLeases

This refactor modernizes the connections view host lookup logic, reduces
redundant RPC queries, and improves maintainability and cache reliability.

Signed-off-by: Konstantin Glukhov <redacted>