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* Remove reference to outdated analytics module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/timeout_16.go

@@ -0,0 +1,10 @@
+// +build go1.6
+
+package analytics
+
+import "net/http"
+
+// http clients on versions of go after 1.6 always support timeout.
+func supportsTimeout(transport http.RoundTripper) bool {
+	return true
+}