(recoup) Spatial gridmap take 3

[Tsar-Salat]

Ports:

• Fixes Massive Radio Overtime, Implements a Spatial Grid System for Faster Searching Over Areas tgstation/tgstation#61422
• Fixes a missing initialize flag set in oranges_ear tgstation/tgstation#63660
• Fixes independent superspace radio headsets (eg Centcom headset) tgstation/tgstation#63765
• Harddel Fix Pack #42 + Better Live Reftracking Support tgstation/tgstation#63877 (fix roundstart runtime with client_contents)
• fixes bug with headsets unsetting channels after moving them tgstation/tgstation#64763
• hopefully fixes unit test failures from things in the spatial grid not having their refs cleared from it tgstation/tgstation#65771
• updates documentation for how the oranges_ear mob optimization works tgstation/tgstation#67056

About The Pull Request

closes #11319

This PR optimizes the radio and searching through areas through the implementation of a new subsystem, SSspatial_grid.

This PR is a recoup of Mato0sz's #6582 2021 pr, with my own additional fixes and more tg fixes.

Why It's Good For The Game

bacon said it was good

kills massive radio overtime. Speed for our server (I need it for storage and smooth movement too)

Testing Photographs and Procedure

Screenshots&Videos

2 milliseconds pretty good!

Changelog

🆑 rkz, Kylerace, LemonInTheDark, Tastyfish, Mat05usz
code: Adds new subsystem to optimize radio and searching areas
/:cl:

[github-actions]

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[Tsar-Salat]

Hm. I should probably implement beauty element before this

[github-actions]

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[github-actions]

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[github-actions]

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[Tsar-Salat]

Dammit

[github-actions]

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[Rukofamicom]

No apparent issues during testmerge, but I would like a secondary code review by Bacon before slapping merge.

[Rukofamicom]

Extended TM uncovered a problem with camera listening, RKZ is already aware of it but making sure someone doesn't slap merge until it's fixed.

[Tsar-Salat]

Extended TM uncovered a problem with camera listening

issue with eye_obj listening, fixed now.

Tested through spamming events and seeing if I could hear relayed speech "New announcement!" from the newscasters.

It did not fix it

[Tsar-Salat]

There we go

[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.