Add remote API support for UniFi Site Manager

- Add remote API mode with automatic controller discovery
- Discover consoles via /v1/hosts endpoint
- Auto-discover sites for each console via integration API
- Use console name from hosts response as site name override for Cloud Gateways
- Support both config-level and per-controller remote mode
- Add example configs for YAML, JSON, and TOML formats
- Remote API uses api.ui.com with X-API-Key authentication
- Automatically discovers all consoles when remote=true and remote_api_key is set

This enables monitoring multiple UniFi Cloud Gateways through a single
API key without requiring direct network access to each controller.

examples/remote_api_example.conf

@@ -0,0 +1,45 @@
+##############################################
+# UniFi Poller Remote API Configuration    #
+# TOML FORMAT - Remote API Example          #
+# Uses UniFi Site Manager API (api.ui.com)  #
+##############################################
+
+[poller]
+debug = false
+quiet = false
+
+[unifi]
+remote = true
+remote_api_key = "YOUR_API_KEY_HERE"
+
+[unifi.defaults]
+save_sites = true
+save_dpi = true
+save_events = true
+save_alarms = true
+save_anomalies = true
+save_ids = true
+save_traffic = true
+save_rogue = true
+save_syslog = true
+save_protect_logs = false
+verify_ssl = true
+
+[prometheus]
+disable = false
+http_listen = "0.0.0.0:9130"
+namespace = "unpoller"
+report_errors = false
+dead_ports = false
+
+[influxdb]
+disable = true
+
+[webserver]
+enable = false
+
+[datadog]
+enable = false
+
+[loki]
+disable = true