NTNet Extensibility (#22908)

Fixes https://github.com/Aurorastation/Aurora.3/issues/21944

Spiritual successor of
https://github.com/Aurorastation/Aurora.3/pull/22352
Cherrypicked changes from the C3 Crew Management branch, this PR
contains all NTNet extensibility features, including Field Relay
construction, off-site camera usage (contingent on standing up remote
hardware and being out of jamming), etc. This also fixes a handful of
outstanding telecomms and view/mobeye-related bugs adjacent to where I
was working.

changes:
- rscadd: "Adds NTNet extensibility, requires new machinery constructed
on away-site z-levels."
- rscadd: "Breaks NTNet Relay machinery into Quantum Relay ('core' obj
on Horizon) and Field Relay (deployable off-site constructions)."
- qol: "Embedded cameras (basically every video camera EXCEPT those
which are installed on walls) can now be viewed from NTNet-connected
z-level, not just connected ones."
- rscadd: "Adds several public camera monitor consoles to the Horizon
(near where public sensor grid feed consoles already exist)."
- rscadd: "Adds some spare camera console boards to Horizon technical
storage."
- qol: "Adds action button for 'cancel-camera-view' verb while viewing
cameras or looking up/down z-level."
- bugfix: "Fixes Jockey comms (frequency was missing from ANTAG_FREQS)."
- bugfix: "Fixes look-up/look-down actions intermittently failing
without first using cancel-camera-view."

code/controllers/subsystems/radio.dm

@@ -156,7 +156,7 @@ SUBSYSTEM_DEF(radio)
 
 	return frequency
 
-// Used to test connectivity to the telecomms network.
+/// Used to test connectivity to the telecomms network.
 /datum/controller/subsystem/radio/proc/telecomms_ping(obj/O, test_freq = PUB_FREQ)
 	SHOULD_NOT_SLEEP(TRUE)
 
@@ -167,7 +167,7 @@ SUBSYSTEM_DEF(radio)
 
 // Some misc procs not technically part of the subsystem, but are related.
 
-//callback used by objects to react to incoming radio signals
+/// Callback used by objects to react to incoming radio signals
 /obj/proc/receive_signal(datum/signal/signal, receive_method, receive_param)
 	SHOULD_NOT_SLEEP(TRUE)