[Feature] Email collect message hooks (#331)

- Add email collect hook on creating conversation
- Merge contact if it already exist

app/services/message_templates/hook_execution_service.rb

@@ -0,0 +1,20 @@
+class MessageTemplates::HookExecutionService
+  pattr_initialize [:message!]
+
+  def perform
+    ::MessageTemplates::Template::EmailCollect.new(conversation: conversation).perform if should_send_email_collect?
+  end
+
+  private
+
+  delegate :inbox, :conversation, to: :message
+  delegate :contact, to: :conversation
+
+  def first_message_from_contact?
+    conversation.messages.outgoing.count.zero? && conversation.messages.template.count.zero?
+  end
+
+  def should_send_email_collect?
+    conversation.inbox.web_widget? && first_message_from_contact?
+  end
+end