Feature: Conversation creation email notifications (#576)

* Clean up the mailers

* Disable assignment mailer if setting is turned off

* Email notifications on conversation create

* Specs

app/mailers/application_mailer.rb

@@ -1,6 +1,7 @@
 class ApplicationMailer < ActionMailer::Base
   default from: ENV.fetch('MAILER_SENDER_EMAIL', 'accounts@chatwoot.com')
   layout 'mailer'
+  append_view_path Rails.root.join('app/views/mailers')
 
   # helpers
   helper :frontend_urls