fix: default elastic geoip to disabled and merge elastic environment

[erikwilson]

Improves elastic behavior by merging in environment changes and defaulting geoip downloading to false.

[ioga]

this syntax requires py 3.9 and I believe we still run on 3.7 and 3.8 sometimes, so I'd suggest using some other way to merge dicts e.g.

    {
                "discovery.type": "single-node",
                "cluster.routing.allocation.disk.threshold_enabled": "false",
                "logger.level": "WARN",
                "ingest.geoip.downloader.enabled": "false",
                **config.get(....
            }