chore: Provider API prototype (#3112)

Enabling Support for Whatsapp via 360Dialog as a prototype for the provider APIs. 

Co-authored-by: Pranav Raj S <pranav@chatwoot.com>

app/controllers/webhooks/whatsapp_controller.rb

@@ -0,0 +1,6 @@
+class Webhooks::WhatsappController < ActionController::API
+  def process_payload
+    Webhooks::WhatsappEventsJob.perform_later(params.to_unsafe_hash)
+    head :ok
+  end
+end