CB Server Docker image (x86) fails to run on Docker-for-Mac on Apple Silicon

The Golang binaries in ns_server (gozip vbmap goport godu minify gosecrets) are currently built with Go 1.8.5, which hasn't been a supported version for nearly four years. In particular, this is causing an odd situation reported by a user (https://github.com/couchbase/docker/issues/165 ) where our official Docker images won't run in Docker on Mac M1, because the binaries don't meet some Mac requirement even for running in emulation.

We should upgrade to something much newer, ideally Go 1.15 or so.