Bring etcd support for bucket DNS federation

- Supports centralized `config.json`
- Supports centralized `bucket` service records
  for client lookups
- implement a new proxy forwarder

vendor/github.com/ugorji/go/codec/fast-path.not.go

@@ -0,0 +1,34 @@
+// +build notfastpath
+
+package codec
+
+import "reflect"
+
+const fastpathEnabled = false
+
+// The generated fast-path code is very large, and adds a few seconds to the build time.
+// This causes test execution, execution of small tools which use codec, etc
+// to take a long time.
+//
+// To mitigate, we now support the notfastpath tag.
+// This tag disables fastpath during build, allowing for faster build, test execution,
+// short-program runs, etc.
+
+func fastpathDecodeTypeSwitch(iv interface{}, d *Decoder) bool      { return false }
+func fastpathEncodeTypeSwitch(iv interface{}, e *Encoder) bool      { return false }
+func fastpathEncodeTypeSwitchSlice(iv interface{}, e *Encoder) bool { return false }
+func fastpathEncodeTypeSwitchMap(iv interface{}, e *Encoder) bool   { return false }
+
+type fastpathT struct{}
+type fastpathE struct {
+	rtid  uintptr
+	rt    reflect.Type
+	encfn func(*encFnInfo, reflect.Value)
+	decfn func(*decFnInfo, reflect.Value)
+}
+type fastpathA [0]fastpathE
+
+func (x fastpathA) index(rtid uintptr) int { return -1 }
+
+var fastpathAV fastpathA
+var fastpathTV fastpathT