ACTION-31: Make clearer role of publishing reports

Goal: help community (especially chair) understand they should register reports and the value of doing so (awareness).

One idea is a big "We have no reports yet!" message near the top of the page, leading people to react and register the reports.

Another idea to ensure that all reports are in the system are periodic reminders to chairs.

I added some links to documentation from the reports block in twig template. We'll want Sorin to highlight this in the new template.

2013-01-24: Static template of reference:
http://www.w3.org/community/src/cgbg2012/static/group-home-missing

Sorin and Ian discussed displaying a call to action:
* There will be a button and a label that says (briefly): Only chairs can add a report.
* If you are logged in and a chair, the button takes you to the publication page.
* If you are logged in and not the chair the button is disabled. (Maybe we include a link for more information about nominating the chair).
* If you are not logged in, you push the button to log in to come back to the page.