Differences between config_site.py and config_main.py

Hi, I've noticed a couple of differences between the files docker/config_site.py and GeoHealthCheck/config_main.py. The latter is containing the variables SQLALCHEMY_TRACK_MODIFICATIONS, GHC_METADATA_CACHE_SECS and GHC_PROBE_DEFAULTS, which are missing in the former. It might be a good idea to add them to the Docker config as well.

As an additional note, config_main.py is using arrays for the variables GHC_PLUGINS and GHC_USER_PLUGINS, but when reading them as env. vars in config_site.py, the values will be strings. That doesn't seem correct to me.