Add nginx cache of 1 minute to all GET API calls

[bwbroersma]

Add proxy_cache, change default proxy_cache_key $scheme$proxy_host$request_uri; to include $remote_user.
Probably set proxy_cache_valid any 1m; to cache all (could only set 200 to 1m and errors shorter).
Add add_header X-Cache-Status $upstream_cache_status;