proxy: remove from config (#2744)

fully remove proxy and make it completely external.
Signed-off-by: Miek Gieben <miek@miek.nl>

core/dnsserver/zdirectives.go

@@ -44,7 +44,6 @@ var Directives = []string{
 	"etcd",
 	"loop",
 	"forward",
-	"proxy",
 	"grpc",
 	"erratic",
 	"whoami",

core/plugin/zplugin.go

@@ -11,7 +11,6 @@ import (
 	_ "github.com/coredns/coredns/plugin/cancel"
 	_ "github.com/coredns/coredns/plugin/chaos"
 	_ "github.com/coredns/coredns/plugin/debug"
-	_ "github.com/coredns/coredns/plugin/deprecated"
 	_ "github.com/coredns/coredns/plugin/dnssec"
 	_ "github.com/coredns/coredns/plugin/dnstap"
 	_ "github.com/coredns/coredns/plugin/erratic"

plugin.cfg

@@ -53,7 +53,6 @@ secondary:secondary
 etcd:etcd
 loop:loop
 forward:forward
-proxy:deprecated
 grpc:grpc
 erratic:erratic
 whoami:whoami