Shortcut for SlashCo.FindWorkshopID that looks up a map's .bsp file under maps/.
.bsp
maps/
Name of the map, with or without the .bsp extension.
If true, addons that aren't currently mounted are also checked.
true
The workshop ID of the addon that contains the map, or nil if none was found.
nil
The matching addon's title, or nil if none was found.