Add luacheck CI and drop node_ownership remnants (#44)

`node_ownership` is long dead, and pollutes the global namespace. Support dropped after ~7 years.

Co-authored-by: BuckarooBanzay <BuckarooBanzay@users.noreply.github.com>

legacy.lua

@@ -106,34 +106,3 @@ function areas.hasOwner(pos)
 	end
 	return false
 end
-
-IsPlayerNodeOwner = areas.isNodeOwner
-GetNodeOwnerName  = areas.getNodeOwnerName
-HasOwner          = areas.hasOwner
-
--- This is entirely untested and may break in strange and new ways.
-if areas.config.legacy_table then
-	owner_defs = setmetatable({}, {
-		__index = function(table, key)
-			local a = rawget(areas.areas, key)
-			if not a then return a end
-			local b = {}
-			for k, v in pairs(a) do b[k] = v end
-			b.x1, b.y1, b.z1 = b.pos1.x, b.pos1.y, b.pos1.z
-			b.x2, b.y1, b.z2 = b.pos2.x, b.pos2.y, b.pos2.z
-			b.pos1, b.pos2 = nil, nil
-			b.id = key
-			return b
-		end,
-		__newindex = function(table, key, value)
-			local a = value
-			a.pos1, a.pos2 = {x=a.x1, y=a.y1, z=a.z1},
-					{x=a.x2, y=a.y2, z=a.z2}
-			a.x1, a.y1, a.z1, a.x2, a.y2, a.z2 =
-				nil, nil, nil, nil, nil, nil
-			a.name = a.name or S("unnamed")
-			a.id = nil
-			return rawset(areas.areas, key, a)
-		end
-	})
-end