Changeable bar sign

The Maltese Falcon on default is now empty and now is the job of bartender to change it.

The icon must 64 x 32 that make it use two tiles.

Existing sign bars:
"Armok's Bar N Grill",
"The Broken Drum",
"The Limbo",
"The Magma Sea",
"The Pink Flamingo",
"The Rusty Axe",
"Meadbay",
"Cindi Kate's",
"The Cavern",
"The Clown's Head",
"The Orchard",
"The Saucy Clown",
"The Damn Wall",
"Whiskey Implant",
"Carpe Carp",
"Robust Roadhouse",
"The Grey Tide",
"The Redshirt",
"Maltese Falcon",
"--------"

Usage: the mob must be on O to access the menu

X = Sign bar
O = Menu pop-up
Y = Ignore attack

YYYY
YXXY
OOOO

The TODO is for future development that will not be scope on this PR.