add mouse locator

[husseljoo]

This is inspired by microsoft power toys "Find my mouse" utility.
I found a open source tools that kind of does this called find-cursor, however it needs to be tweaked a bit to be incorporated to my config.
Also I like the dimming screen part of the powertoys tool, but need to look into this later.

Moreover, I need to read more about subsequent keybindings in xmonad, as I want to bind this tool to Ctrl+Ctrl without interfering with other Ctrl+ program specific bindings.