mw/federation: add federation back as separate mw for k8s (#929)

* mw/federaration

This PR add the federation back as a middleware to keep it more
contained from the main kubernetes code.

It also makes parseRequest less import and pushes this functionlity down
in the k.Entries. This minimizes (or tries to) the importance for the
qtype in the query. In the end the qtype checking should only happen
in ServeDNS - but for k8s this might proof difficult.

Numerous other cleanup in code and kubernetes tests.

* up test coverage

middleware/autopath/autopath.go

@@ -1,8 +1,6 @@
-package autopath
-
 /*
-Autopath is a hack; it shortcuts the client's search path resolution by performing
-these lookups on the server...
+Autopath package implement autopathing. This is a hack; it shortcuts the
+client's search path resolution by performing these lookups on the server...
 
 The server has a copy (via AutoPathFunc) of the client's search path and on
 receiving a query it first establish if the suffix matches the FIRST configured
@@ -31,6 +29,7 @@ func (m Middleware ) AutoPath(state request.Request) []string {
 	return []string{"first", "second", "last", ""}
 }
 */
+package autopath
 
 import (
 	"log"
@@ -108,7 +107,6 @@ func (a *AutoPath) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Ms
 		if err != nil {
 			// Return now - not sure if this is the best. We should also check if the write has happened.
 			return rcode, err
-
 		}
 		if i == 0 {
 			firstReply = nw.Msg