feat(publicip): resilient public ip fetcher (#2518)

- `PUBLICIP_API` accepts a comma separated list of ip data sources, where the first one is the base default one, and sources after it are backup sources used if we are rate limited.
- `PUBLICIP_API` defaults to `ipinfo,ifconfigco,ip2location,cloudflare` such that it now has `ifconfigco,ip2location,cloudflare` as backup ip data sources.
- `PUBLICIP_API_TOKEN` accepts a comma separated list of ip data source tokens, each corresponding by position to the APIs listed in `PUBLICIP_API`.
- logs ip data source when logging public ip information
- assume a rate limiting error is for 30 days (no persistence)
- ready for future live settings updates
  - consider an ip data source no longer banned if the token changes
  - keeps track of ban times when updating the list of fetchers

Dockerfile

@@ -205,7 +205,7 @@ ENV VPN_SERVICE_PROVIDER=pia \
     # Public IP
     PUBLICIP_FILE="/tmp/gluetun/ip" \
     PUBLICIP_ENABLED=on \
-    PUBLICIP_API=ipinfo \
+    PUBLICIP_API=ipinfo,ifconfigco,ip2location,cloudflare \
     PUBLICIP_API_TOKEN= \
     # Storage
     STORAGE_FILEPATH=/gluetun/servers.json \