Update tap targets over ws (#901)

Update tappers via websocket instead of by env var. This way the DaemonSet doesn't have to be applied just to notify the tappers that the tap targets changed. The number of tapper restarts is reduced. The DaemonSet still gets applied when there is a need to add/remove a tapper from a node.

tap/passive_tapper.go

@@ -59,7 +59,6 @@ var memprofile = flag.String("memprofile", "", "Write memory profile")
 
 type TapOpts struct {
 	HostMode          bool
-	FilterAuthorities []v1.Pod
 }
 
 var extensions []*api.Extension                     // global
@@ -90,12 +89,6 @@ func StartPassiveTapper(opts *TapOpts, outputItems chan *api.OutputChannelItem,
 	extensions = extensionsRef
 	filteringOptions = options
 
-	if opts.FilterAuthorities == nil {
-		tapTargets = []v1.Pod{}
-	} else {
-		tapTargets = opts.FilterAuthorities
-	}
-
 	if *tls {
 		for _, e := range extensions {
 			if e.Protocol.Name == "http" {