Repair menu highlighting, both for main menu and submenus

During the recent improvements made on the website, the menus and
submenu highlighting for selected menus fell into disarray.
Correction requires changes to the CSS and templates both, because
Django doesn't really have a convenient way to set variables in
templates to use to solve this.

There are still a few submenu items highlighting not working even
after this commit. More work needs to be done.

Generalize VMWare links page into a previous litigation links page

More will need to be added to make it true, this is the first step.

activities: add page for “What We Do”.

This is a first pass at content for the activities page, which is the
landing page for the top-bar menu item of “What We Do”.