Adds info about Holsters to the inventory UI

[bombasticSlacks]

Summary

Interface "Adds info about Holsters to the inventory UI"

Purpose of change

With all the new ablative pockets, and single item holding ripoff pockets and slots I and some other have been adding it may not be intuitive for new players. This should help make it clearer, or at least give the player more immediate info.

Describe the solution

Adds a new row to the Inventory UI that explains how many holsters you have, how many are in use, and how much of your remaining volume is "holsters" which are normally more selective pockets.

Describe alternatives you've considered

Waiting till after @KorGgenT stuff. I didn't realize I was writing something that iterated over worn until I was about halfway through ( I was copying and pasting other functions and modifying them). If this gets merged before your stuff (it shouldn't) I'll make a patch for your PR.

Testing

Loaded up the game, gave myself some pockets, can parse the info.

Additional context