Bug 1043366 - Add Berlin office twitter, irc and wiki info

I don't know if this page counts as a "space operation guide". For the other spaces that have operation guides, they're mostly about how to book the community space for events (e.g. https://wiki.mozilla.org/People:MozSpaces_Guidelines:Mountain_View) but this new page for Berlin seems like more general info about the office. I'm not sure what text to use as the link... maybe just "Wiki"