Machinery EMP Resistance (Wild Singulo Fixes)

[Azrun]

[balance][bug - major][input wanted]

About the PR

• Singularities will no longer attempt to eat things that do not exist. [Bug]
• Limits Camera's to only queue only recalculation when multiple EMPs have happened in the 90 second disable window. [Performance]
  • This does make it so you can not add additional delay until the cameras comes back online. [Balance]
• Limits APC battery drain from EMP to once every 90 seconds. [Performance] [Balance]
  • Battery drain from EMP can be mitigated by turning off APC due to implementation [Balance]
• Limits EMP on standard machinery to only procing overlay and power drain to once per second.

This does end up being an "unintentional" EMP Grenades, Wave Gun, EMP* nerf as there will be a limit to how often those items can impact /obj/machinery.

---

Addresses a number of runtimes that occur due to spawned tasks having their object disposed of.
Targets performance improvements when multiple EMPs go off to limit the number of new tasks spawned.

Why's this needed?

Runtimes are bad.
Resolve unusual behavior from multiple EMP's going off. Like when the station is covered in singularities...

(u)Azrun:
(+)Machinery, cameras, and APCs are more EMP resistant.  Cameras will come back online after being EMPed after 90 seconds, duration will no longer be extended with additional EMPs.

[github-actions]

Created discussion thread: https://forum.ss13.co/showthread.php?tid=15511

[flrsh]

Can you rephrase Will no longer be able to re-EMPs to reset duration that camera is disabled until it comes back online. so that it's more clear?

[Azrun]

@ZeWaka you want me to change it for consistency or is this pending anything else?