add working group calendar to the wg page

[benoitc]

Right now the calendar os only shown on the main page. But it would be useful to also find it on the wg page. Sone someone can ask to join the events. Thoughts?

[starbelly]

We were showing this, but it was removed because you would click on a working group's calendar and see two events. I think you may have commented that it may not be that useful.

That said, I'm ok with putting it back if we think it's useful.

[benoitc]

AFAIK I pointed the way the another org was doing by showing the next coming event.IMO something similar would also work. Would it be simpler?