Switch to go-dnsmasq as local DNS resolver

[janeczku]

I propose a streamlined approach to fix the DNS limitation of musl-libc based Docker containers by replacing dnsmasq and all the DNS workaround scripts with https://github.com/janeczku/go-dnsmasq.
This is essentially a slimmed down Golang fork of dnsmasq that has a feature to replicate the resolv.conf search keyword functionality.

Advantages:

• True dynamic "search domain" DNS resolution instead of a semi-static hostslist
• Instantly available on container start (no DNS fix setup delay)
• No bash scripting necessary
• Works OOB on Tutum, Kubernetes and any other DNS based service discovery platform
• Base image looses an extra 1MB weight :-)

You may try it out with the docker-composer.yml or tutum.yml in the branch of this PR: https://github.com/janeczku/base-alpine/tree/go-dnsmasq

[neilellis]

Hey sorry I've been off line for a little while I'm taking a look at your suggestion which seems like a very good one.