Client|UI: Adjusting mouse trapping behavior wrt task bar

As a rule, the mouse is untrapped when the task bar is opened. Loading
a game will hide the task bar and automatically trap the mouse.
Client|UI: Improved integration between task bar, console, and game

The console widget is now a more integral part of the task bar. The
command line is in the task bar, and when it gains focus, the log
history opens.

When the task bar is open, Esc will now first close and unfocus the
console. The second press of Esc will close the task bar.

Shift-Esc will always move focus to the console command line.

Clicking on the LegacyWidget will clear UI focus, allowing the game
to receive events.