[Enhancement] Handle Multiple Leagues Simultaneously

[JaredKreft]

Currently, if I'm active in multiple leagues and using Acquisition for each of them, I have to run multiple copies of Acquisition, one for each league.

There are several problems with this. The first is that each copy does a pull from POE's API both initially and on the schedule you set, so you start getting "too many requests" errors if you're running more than one account in two leagues.

Now, this may seem like it would require a big rewrite, but it can actually be done by encapsulating the current objects that track a league's items into a single object which you tie to its own tab and then support multiple tabs.

A bonus would be the ability to search just this league or all leagues with a checkbox.