Creates a framework for per-faction Alt Titles (#19671)

Creates a framework to restrict certain alt titles to certain factions.

As an example and natural logical consequence:
"Corporate Reporter" can only be used by Corporate employees
"Freelance Journalist" can only be used by Independent crew

I plan to use this system in a later PR.

---------

Signed-off-by: FlamingLily <80451102+FlamingLily@users.noreply.github.com>

code/modules/client/preference_setup/occupation/occupation.dm

@@ -517,6 +517,11 @@
 	if (!job)
 		return
 	var/choices = list(job.title) + job.alt_titles
+	for(var/t in choices)
+		if(!isnull(job.alt_factions))
+			if (src.faction in job.alt_factions[t])
+				continue
+			choices -= t
 	if((GLOB.all_species[src.species].spawn_flags & NO_AGE_MINIMUM))
 		return choices
 	for(var/t in choices)