Add a hotkey to see the last alarm position

[Stan]

Currently when attacked you have no way to quickly go there. With a hotkey one could just press spacebar for instance and go there.

Reported here ​https://wildfiregames.com/forum/index.php?/topic/27053-request-battle-sounds/

This will be helped with #3491

[Minohaka]

Please make the space bar be that shortcut

[elexis]

Not sure if space bar is the right default key assignment, but the idea about hotkeys is that you can assign your own.

#5132

[wraitii]

Kinda like the idea of space bar for this type of stuff, but would probably be useful now because having to click on the button thingy is annoying

[Imarok]

Should this work similar to the button in #5132 (follows the unit that got attacked, if dead focuses the position of the attack) or should this always show the position of the attack?

[Imarok]

In 25715:

Add a hotkey to focus on the last attack alarm

Fix #5608

Differential Revision: ​https://code.wildfiregames.com/D4101