Improve the Try XWiki Cloud area

I propose the following improvements to the Cloud & Hosted:

Instead of

Host with us and get your wiki up and running in no time, in a stable and secure environment.

use:

Open a 10 days trial of XWiki in the XWiki SAS cloud in one minute

Then in a second step change the button to a form to choose the wiki name and get directly to the second form on xwiki.com.