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* Remove reference to outdated analytics module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/integrations.go

@@ -0,0 +1,44 @@
+package analytics
+
+// This type is used to represent integrations in messages that support it.
+// It is a free-form where values are most often booleans that enable or
+// disable integrations.
+// Here's a quick example of how this type is meant to be used:
+//
+//	analytics.Track{
+//		UserId:       "0123456789",
+//		Integrations: analytics.NewIntegrations()
+//			.EnableAll()
+//			.Disable("Salesforce")
+//			.Disable("Marketo"),
+//	}
+//
+// The specifications can be found at https://segment.com/docs/spec/common/#integrations
+type Integrations map[string]interface{}
+
+func NewIntegrations() Integrations {
+	return make(Integrations, 10)
+}
+
+func (i Integrations) EnableAll() Integrations {
+	return i.Enable("all")
+}
+
+func (i Integrations) DisableAll() Integrations {
+	return i.Disable("all")
+}
+
+func (i Integrations) Enable(name string) Integrations {
+	return i.Set(name, true)
+}
+
+func (i Integrations) Disable(name string) Integrations {
+	return i.Set(name, false)
+}
+
+// Sets an integration named by the first argument to the specified value, any
+// value other than `false` will be interpreted as enabling the integration.
+func (i Integrations) Set(name string, value interface{}) Integrations {
+	i[name] = value
+	return i
+}