/list - Re-add separate categories by rank

I think it would be nice if /list had separate categories by rank, as was the case before. Ordered in the same order as the tab list, so owner, sr. admin, admin, dev, mod, Celestial, Emperor, etc. Currently it's only separated by staff and players. With this change, there would be more than just the 2 categories, instead 1 for each rank. In my opinion, /list can function as an extension of the tab list, if too many players are online. Thus, it makes sense for it to be sorted in this way. This was also a feature in the Essentials /list. The old implementation was flawed (it would actually show SMP/Factions ranks if you didn't have an RPG rank), but I think it was nice to have players separated by rank.