Browser support section should be more visible

For now:

• there is no link in the Install and Admin root page
• in the Hardware and Software page, the paragraph related to browser support is the last tiny part of the page.

I think it could be one of the most important information once people are insterested to our platform, before knowing if you have enough CPU on the machine that will host nuxeo.

-> pull up this paragraph in the page
-> add a link to the Browser Support anchor in the root page / For testing purpose box
-> See if it could be relevant in other spaces / root pages