Use etcd embed package, switch apiserver to use etcdv3

[r2d4]

Etcd's embed package does a lot of the heavy lifting we were doing previously, as well as configure etcd v3 endpoints.

[codecov-io]

Codecov Report

Merging #1720 into master will increase coverage by 0.54%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #1720      +/-   ##
==========================================
+ Coverage   36.23%   36.78%   +0.54%     
==========================================
  Files          51       51              
  Lines        3367     3317      -50     
==========================================
  Hits         1220     1220              
+ Misses       1966     1916      -50     
  Partials      181      181

Impacted Files	Coverage Δ
pkg/localkube/etcd.go	0% <0%> (ø)	⬆️
pkg/localkube/apiserver.go	0% <0%> (ø)	⬆️

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[r2d4]

Fixes #1254

[dlorenc]

Can you verify that an in-place upgrade works? Basically start minikube without this, deploy a bunch of stuff, then do a minikube start with this.

[r2d4]

I will try, but I don't think it will work. The upgrade from 1.6 to 1.7 won't work without a recreate either. I'm not sure exactly what we can do to support this sort of stuff.

[r2d4]

Well, I was wrong in both cases. It should work upgrading from 1.6.x => 1.7.0 and etcd2 => etcd3.

minikube start --kubernetes-version v1.6.4
minikube stop
minikube start --kubernetes-version v1.7.0

[dlorenc]

LGTM, but let's get a release with 1.7 out before we merge.