add heat seaker mode

[SwissalpS]

shows on hud markers with the values of the surrounding blocks.
reason: sometimes it is hard to spot a block that is silently building up penalty.

variant of this would be a mode that when you use tool, that block is added to players hud
updating it's values for x seconds or until you go there again and toggle with tool.

Wasn't it @6r1d who thought all along the postool was to do that?

[SwissalpS]

we probably won't add this on main branch as this function may be more than we agreed this mod to do.