Full revert of #79995 (tri-ai station trait). Partal revert of #81681 (human ai) (#84850)

#79995 removed the verb and secrets button for no reason. This means you
can no longer decide to do tri-ai in the lobby, you have to do it next
round or make players suffer thru another init cycle.

**__In general systems that require things be decided the previous round
are really fucking annoying and should be minimized to only specific
things that absolutely have to for technical reason.__**

This is not one of them.

I do not have the time to redesign the station trait to make use of the
existing admin code so this is a full revert instead.

If the station trait is re-added, it should be done so without removing
the secrets button or admin verb.

#81681 had an undocumented and un-atmoized change, in that it removed a
job related signal needlessly, that undocumented change has been
reverted because this system used that signal.

@Fikou 
@JohnFulpWillard 

(also cc @tralezab and @Ghommie as you merged the reverted prs)

code/controllers/subsystem/job.dm

@@ -389,6 +389,7 @@ SUBSYSTEM_DEF(job)
 	//Setup new player list and get the jobs list
 	JobDebug("Running DO, allow_all = [allow_all], pure = [pure]")
 	run_divide_occupation_pure = pure
+	SEND_SIGNAL(src, COMSIG_OCCUPATIONS_DIVIDED, pure, allow_all)
 
 	//Get the players who are ready
 	for(var/i in GLOB.new_player_list)