The Content view will soon need some special behavior compared to <ez-server-side-content> custom element. So core components should define a <ez-content-view> custom elements that extends <ez-server-side-content>

So this story involves several "tasks" (commits/PR)

• add <ez-content-view> to core-components with unit tests
• change locationview.html.twig template to generate the new custom element
• remove the class .ez-content-view and update the corresponding CSS files