[Feature] Email collect message hooks (#331)

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

app/services/widget/token_service.rb

@@ -0,0 +1,21 @@
+class Widget::TokenService
+  pattr_initialize [:payload, :token]
+
+  def generate_token
+    JWT.encode payload, secret_key, 'HS256'
+  end
+
+  def decode_token
+    JWT.decode(
+      token, secret_key, true, algorithm: 'HS256'
+    ).first.symbolize_keys
+  rescue StandardError
+    {}
+  end
+
+  private
+
+  def secret_key
+    Rails.application.secrets.secret_key_base
+  end
+end