Enable gzip compression in nginx

[fhemberger]

Looks like gzip compression is currently not enabled in nginx (Content-Encoding header is missing), but especially the API calls would benefit from it.

gzip            on;
gzip_min_length 1000;
gzip_proxied    no-store;
gzip_types      gzip_types text/plain text/css application/javascript application/json text/xml application/xml application/xml+rss image/svg+xml;

[aaronpk]

Thanks! gzip compression is now on.