[Feature]: Category Missing Item Display

[rwagner00]

Describe the feature

A user should be able set a category such that it will display items that could be present in that category, even if they are missing. A use case for this would be for custom consumable categories, so that a player could set up their raid/dungeon consumables and see at a glance that they are out of something.

Describe the implementation

When I go to config options and enter the settings menu for which items belong to a category, then there should be a checkbox to enable the display of missing items. Once that box is checked, all possible items will show in that category, with grayed out icons for items that are missing.