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.
Merge pull request #6671 from Zuhayr/finiwig

Added goddamn atrocious wig for Earthcrusher.
Merge pull request #6681 from Baystation12/dev-freeze

Dev freeze -> Dev
Basically ripped over /tg/'s powernet and cable code into our own codebase.

Keeps Z-level code as it was.
Modifies/restores powernet procs as necessary to match our own implementation changes.
/tg/'s solar code with a fix for the solar control computer not refreshing on user input.
testing fix for nui resources

Signed-off-by: Mloc-Argent <colmohici@gmail.com>
fixes #6299

Signed-off-by: Mloc <colmohici@gmail.com>
Converts all machines relying on RandomAPCWires() to the new wire datum system.
Merge pull request #6709 from Mloc/bs12-server

testing fix for nui resources
Merge pull request #6707 from Mloc/bs12-overflow

fixes #6299
Fixes #6321
Fixes #6608
Makes the number of load/storable character slots a configurable value.
Merge pull request #6711 from PsiOmegaDelta/SlotConfig

Configurable number of character slots