ws: Show a login page for any .html resource being accessed

For other resources besides the main page, show a login page if user
doesn't have a cookie.

One big difference, we now refresh the page after completing a
sucessful login.
static: Change the styles of login page when shown inline

When not logging into cockpit as a whole, just show a basic login
screen on a white background. This will help not confuse users as
to what they're logging into.
tools: Ignore another glib leak
examples: Add example for embedding terminal
examples: Add example for pinging the server