Changes alien_whitelist to an assoc list of ckeys

[Atermonera]

This makes me sad:

This change maybe addresses that? It can't be slower.

[Spookerton]

Parsing it all once at load to (like the PR name, before the regex add) a structure like list(ckey = list(name, name, ...), ...) may be preferable in the end, since then the matter of is_alien_whitelisted reduces to just

.../is_alien_whitelisted(mob/M, species/S)
  return (S?.name in alien_whitelist?[ckey(M?.ckey)])

(which is terribly resilient to nulls, as an aside)

[Spookerton]

nb: because this uses the single monolithic file approach, the regex the whole thing or pre-parse the whole thing approaches are necessary. Were it sqlite, json-per-user in player_saves, or some other oob store, you could load the data per-client, reducing work and making in-game editing of allow lists more reasonable.

(this is not directly PR relevant ofc; musings for a potential future redo)

[Spookerton]

Closing this since you already put in an alternative. Reopen if necessary.