Adds Hivenet echoes for Vaurcae (#22140)

First PR. Adds mechanical representation of faint Hivenet echoes for
Vaurcae. Like the lore, only they can pick them up.

It's designed for a lot of variety so as to trigger every 3-5 minutes
without boring players. All together, there's 500 different echoes.
There are three categories of broadcasts (gossip, happy, tense) split
between "starter" and "response" messages to imitate two vaurcae
talking. These make up 380/500.

Gossip can occasionally have a singular, joined echo to represent only a
single vaurcae talking for extra variety. Happy is less common and tense
is the rarest, implying possible danger.

There's also echoes of projections, on a separate 4-8m timer with 120
different sensations for the remaining echoes.

Hivenet should never feel empty again and echoes extend past being
fluff, they can prompt roleplay since they'd ICly be just as valid as an
in-round broadcast. Echoes are automatically disabled in the Lemurian
Sea to represent the Fog there and can be manually toggled by Admins &
Storytellers for gimmicks or events.

---------

Signed-off-by: runecap <43975590+runecap@users.noreply.github.com>
Co-authored-by: VMSolidus <evilexecutive@gmail.com>

code/modules/admin/admin_verbs.dm

@@ -162,6 +162,7 @@ GLOBAL_LIST_INIT(admin_verbs_spawn, list(
 	))
 
 GLOBAL_LIST_INIT(admin_verbs_server, list(
+	/datum/admins/proc/ToggleEchoes, //Toggles if Vaurcae receive faint echoes (fluff) of the wider Hivenet. Useful for events or gimmicks.
 	/datum/admins/proc/capture_map_part,
 	/client/proc/Set_Holiday,
 	/datum/admins/proc/startnow,