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>

spec/controllers/webhooks/whatsapp_controller_spec.rb

@@ -0,0 +1,12 @@
+require 'rails_helper'
+
+RSpec.describe 'Webhooks::WhatsappController', type: :request do
+  describe 'POST /webhooks/whatsapp/{:phone_number}' do
+    it 'call the whatsapp events job with the params' do
+      allow(Webhooks::WhatsappEventsJob).to receive(:perform_later)
+      expect(Webhooks::WhatsappEventsJob).to receive(:perform_later)
+      post '/webhooks/whatsapp/123221321', params: { content: 'hello' }
+      expect(response).to have_http_status(:success)
+    end
+  end
+end