Adjust hierarchy on email settings page, fix alignment

Created by: quinnkeast

In the redesign, we introduced a container element. This container is intended to improve hierarchy and layout, but as it was implemented on the "Emails" settings page, it was just a background for the content.

This PR rearranges the page content a bit to use the container intentfully to create better hierarchy of content, rather than as a background. It also fixes an issue with vertical centre alignment for the items in each email row.