[RFE] Add support for GeoIP and custom geoip DB

[phvalguima]

Add support for opensearch-geospatial plugin. This plugin pulls the IPs database from an upstream source as configured by ingest.geoip.downloader.endpoint.default and copy its contents to the plugin's config directory.

We should (1) support this feature and make sure the database is downloaded and copied to the right folder under the snap; and (2) provide a config option to set the endpoint default above.

The alternative for the default is for the user to manually download the database file and then, at each ingest pipeline creation:

{
  ...
  "processors" : [
    {
      "geoip" : {
        "field" : "ip",
        "target_field" : "geo",
        "database_file" : "my-db-file"
      }
    }
  ]
}

[github-actions]

https://warthogs.atlassian.net/browse/DPE-4810