MM-12389 Update segment library to v3 (#11472)

* Update analytics-go dependency

* Migrate from segment library v2 to v3

* Reinclude gorilla/handlers module

* Fix missing module

* Remove reference to outdated analytics module

vendor/github.com/segmentio/analytics-go/executor.go

@@ -0,0 +1,53 @@
+package analytics
+
+import "sync"
+
+type executor struct {
+	queue chan func()
+	mutex sync.Mutex
+	size  int
+	cap   int
+}
+
+func newExecutor(cap int) *executor {
+	e := &executor{
+		queue: make(chan func(), 1),
+		cap:   cap,
+	}
+	go e.loop()
+	return e
+}
+
+func (e *executor) do(task func()) (ok bool) {
+	e.mutex.Lock()
+
+	if e.size != e.cap {
+		e.queue <- task
+		e.size++
+		ok = true
+	}
+
+	e.mutex.Unlock()
+	return
+}
+
+func (e *executor) close() {
+	close(e.queue)
+}
+
+func (e *executor) loop() {
+	for task := range e.queue {
+		go e.run(task)
+	}
+}
+
+func (e *executor) run(task func()) {
+	defer e.done()
+	task()
+}
+
+func (e *executor) done() {
+	e.mutex.Lock()
+	e.size--
+	e.mutex.Unlock()
+}