Stash variables for performance

The idea is to use variables to improve the performance in first place for external apps like procurement, but it can also be implemented for game performance

There are lots of possibilities, like for example a boolean variable for each tab that records if it has changed since last time (like cache), and so it doesn't need to reload everything in the stash everytime if there are no changes (this would practically load instantaneously procurement when you play only new leagues for example and also reduce server request)