[MIRROR] Moves lua off of the timer subsystem and onto its own internal scheduler. (#26980)

* Moves lua off of the timer subsystem and onto its own internal scheduler. (#82131)

## About The Pull Request
Lua uses the timer subsystem, which can end up holding the entire timer
subsystem if lua is creating a lot of timers.
The solution to this is to use an internal scheduler instead so that the
load gets placed onto the lua subsystem.

## Why It's Good For The Game
Performance improvement when using lua scripts.

## Changelog
🆑
refactor: Auxlua no longer uses the timer subsystem to get stuff done,
lua scripts shouldn't slow down timers anymore.
/🆑

---------

Co-authored-by: Watermelon914 <3052169-Watermelon914@ users.noreply.gitlab.com>

* Moves lua off of the timer subsystem and onto its own internal scheduler.

---------

Co-authored-by: Watermelon914 <37270891+Watermelon914@users.noreply.github.com>
Co-authored-by: Watermelon914 <3052169-Watermelon914@ users.noreply.gitlab.com>

lua/timer.lua

@@ -0,0 +1,106 @@
+local SS13 = require("SS13_base")
+local Timer = {}
+
+__Timer_timers = __Timer_timers or {}
+__Timer_callbacks = __Timer_callbacks or {}
+
+function __add_internal_timer(func, time, loop)
+	local timer = {
+		loop = loop,
+		executeTime = time + dm.world:get_var("time")
+	}
+	__Timer_callbacks[tostring(func)] = function()
+		timer.executing = false
+		if loop and timer.terminate ~= true then
+			timer.executeTime = dm.world:get_var("time") + time
+		else
+			__stop_internal_timer(tostring(func))
+		end
+		func()
+	end
+	__Timer_timers[tostring(func)] = timer
+	return tostring(func)
+end
+
+function __stop_internal_timer(func)
+	local timer = __Timer_timers[func]
+	if timer and not timer.executing then
+		__Timer_timers[func] = nil
+		__Timer_callbacks[func] = nil
+	else
+		timer.terminate = true
+	end
+end
+
+__Timer_timer_processing = __Timer_timer_processing or false
+SS13.state:set_var("timer_enabled", 1)
+__Timer_timer_process = function(seconds_per_tick)
+	if __Timer_timer_processing then
+		return
+	end
+	__Timer_timer_processing = true
+	local time = dm.world:get_var("time")
+	for func, timeData in __Timer_timers do
+		if timeData.executing == true then
+			continue
+		end
+		if over_exec_usage(0.85) then
+			sleep()
+		end
+		if time >= timeData.executeTime then
+			SS13.state:get_var("functions_to_execute"):add(func)
+			timeData.executing = true
+		end
+	end
+	__Timer_timer_processing = false
+end
+
+function Timer.wait(time)
+	local next_yield_index = __next_yield_index
+	__add_internal_timer(function()
+		SS13.SSlua:call_proc("queue_resume", SS13.state, next_yield_index)
+	end, time * 10, false)
+	coroutine.yield()
+end
+
+function Timer.set_timeout(time, func)
+	Timer.start_loop(time, 1, func)
+end
+
+function Timer.start_loop(time, amount, func)
+	if not amount or amount == 0 then
+		return
+	end
+	if amount == -1 then
+		return __add_internal_timer(func, time * 10, true)
+	end
+	if amount == 1 then
+		return __add_internal_timer(func, time * 10, false)
+	end
+	local callback = SS13.new("/datum/callback", SS13.state, "call_function")
+	local timedevent = dm.global_proc("_addtimer", callback, time * 10, 40, nil, debug.info(1, "sl"))
+	local doneAmount = 0
+	local newFunc = function()
+		func()
+		doneAmount += 1
+		if doneAmount >= amount then
+			Timer.end_loop(timedevent)
+		end
+	end
+	__add_internal_timer(newFunc, time * 10, true)
+	return newFunc
+end
+
+function Timer.end_loop(id)
+	__stop_internal_timer(id)
+end
+
+function Timer.stop_all_loops()
+	for id, data in __Timer_timers do
+		if data.loop then
+			Timer.end_loop(id)
+		end
+	end
+end
+
+return Timer