Boost provides static page caching for Drupal enabling a very significant performance and scalability boost for sites that receive mostly anonymous traffic. For shared hosting this is your best option in terms of improving performance. On dedicated servers, you may want to consider Varnish instead.
Contact Storage module will provide storage for Contact messages which are fully-fledged entities in Drupal 8.
This plus core contact module aim to provide functionality equivalent to the base-features of Webform or Entity Form.
Contact Storage module provides storage for all the messages submitted through the forms on your site as well as views integration to manage them.