Flash experiments

• <%= link_to 'redirect with flash notice', flash_redirect_with_notice_path, class: :button %>
• <%= link_to 'redirect with flash alert', flash_redirect_with_alert_path, class: :button %>
• <%= link_to 'render notice', flash_render_notice_path, class: :button %>
• <%= link_to 'turbo notice', flash_turbo_notice_path, class: :button, 'data-turbo-method': :post %>