[Feature] Email collect message hooks (#331)

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

app/controllers/api/v1/widget/base_controller.rb

@@ -0,0 +1,29 @@
+class Api::V1::Widget::BaseController < ApplicationController
+  private
+
+  def conversation
+    @conversation ||= @contact_inbox.conversations.find_by(
+      inbox_id: auth_token_params[:inbox_id]
+    )
+  end
+
+  def auth_token_params
+    @auth_token_params ||= ::Widget::TokenService.new(token: request.headers[header_name]).decode_token
+  end
+
+  def header_name
+    'X-Auth-Token'
+  end
+
+  def set_web_widget
+    @web_widget = ::Channel::WebWidget.find_by!(website_token: permitted_params[:website_token])
+    @account = @web_widget.account
+  end
+
+  def set_contact
+    @contact_inbox = @web_widget.inbox.contact_inboxes.find_by(
+      source_id: auth_token_params[:source_id]
+    )
+    @contact = @contact_inbox.contact
+  end
+end