Cleans up used_radios

The used_radios handling was too specific to be in mob/living/say.
Subtypes had to figure out what to pass for used_radios anyways, they
can also decide how to handle radio use (or if talking into radios even
applies to their mob type).
Allows properly keyed headsets to broadcast in robot talk and/or hivemind

Adds :0 speech code which activates radio-defined behaviour.
Removes unused radio code, world print in forcesay
Ports /tg's cable and powernet code to our code base.
Added goddamn atrocious wig for Earthcrusher.
Cherry picking breaker box fix.
Adds diagonal cable check on breaker box state change.
Fixes engineering ERT loadout area

ERT engineers had to climb over a table to be able to reach all their gear.
Re-organizes the area to avoid this.
Merge pull request #6671 from Zuhayr/finiwig

Added goddamn atrocious wig for Earthcrusher.
Merge pull request #6679 from PsiOmegaDelta/ERTEngineers

Fixes engineering ERT loadout area
Merge pull request #6681 from Baystation12/dev-freeze

Dev freeze -> Dev
Better typing sprite
disable typing indicator.
Merge pull request #6685 from DJSnapshot/dev-freeze

Better typing sprite and disabling the typing indicator
Fixes #6682
Fixes #6684
Fixes being unable to knock on windows.
Merge pull request #6688 from Zuhayr/dev-freeze

Dev freeze fixes
Added Galactic Common to the AI.
Fixes #6695