Small fixes from a full walkthrough of the site

We went through every screen and flow as a customer would, in six languages, on a laptop and on a phone. Most of it was fine. What we fixed: when you are signed in on a phone, the header no longer runs off the screen; the portal, admin and logout links sit in the menu. The sign-in page, the portal, the thank-you page and the 404 page now have their own tab title instead of the home page's. The address field for a trial site checks your input again in current browsers, so you see straight away that only lowercase letters, digits and hyphens work. The template preview no longer sits inside the publish form, and the preview also works in older browsers that do not send the newer request headers. On the home page the Azure card no longer names cities in its description, because the places next to the cloud name already say where your site runs.