Nginx config changes

Related issue #7 A handful of nginx configuration changes based on ctek recommendations

• Add /healthcheck/ location to nginx so that proxy application doesn't control health of container
• Add nginx error_log to stdout
• Add nginx custom logging format
• Hard code /api/xpublish/ location (which was previously set with env var)
• Move nginx specifcation into default instread of *.usgs.gov server name

README.md

@@ -17,11 +17,11 @@ This repository contains a Dockerfile for deploying a STAC/Zarr -> OpenDAP serve
 
 **stop container**
 
-`docker stop cat_to_xpub`
+`docker stop cattoxpub`
 
 **remove container**
 
-`docker rm cat_to_xpub`
+`docker rm cattoxpub`
 
 **run**