As a Project Developer, I want to add site search capability to my project

This story is done when:

• There is a separate installable plugin in the Essentials dashboard
• Installing the plugin adds a "search" box in the top left of the header of the page template
• Installing the plugin adds a search results page
• The search results page supports paging
• The search results page reuses the list component that is also used for the news, events and blogs overview
• Out-of-scope: selecting the facet scope, similar to blogs, this cannot be picked through the Channel Manager UI yet