middleware.cfg to configure middleware directives (#496)

* Use go generate to build middleware setup based on middleware.cfg
Init default config

* generated files

* Move gen to an isolated area

* rename files

* PR review updates

* undo readme

core/dnsserver/zdirectives.go

@@ -0,0 +1,36 @@
+// generated by directives_generate.go; DO NOT EDIT
+package dnsserver
+
+
+// Directives are registered in the order they should be
+// executed.
+//
+// Ordering is VERY important. Every middleware will
+// feel the effects of all other middleware below
+// (after) them during a request, but they must not
+// care what middleware above them are doing.
+
+var directives = []string{
+		"root",
+		"bind",
+		"trace",
+		"health",
+		"pprof",
+		"prometheus",
+		"errors",
+		"log",
+		"chaos",
+		"cache",
+		"rewrite",
+		"loadbalance",
+		"dnssec",
+		"file",
+		"auto",
+		"secondary",
+		"etcd",
+		"kubernetes",
+		"proxy",
+		"httpprox",
+		"whoami",
+		"erratic",
+}