#24 Inventory and Quickslots Rework

The goal is to ensure the inventory is actually working, allowing for picking up items and adding to the inventory screen. Note: The methods for when to update the inventory and quickslot UIs are a bit ineffecient and could use some work in the future. ## Features * Rework of the InventoryManager to support both the inventory and Quickslot management * Rework of QuickSlots * UI now autogenerates the quickslot items depending on the first x number of inventory slots * UI was moved back to the bottom of the screen to allow for 10 to fit quickslots to comfortably fit on screen * Basic inventory screen * There's nothing that can be done from within the inventory UI currently * Placing or throwing a block removes from the inventory * The Held Block will hide itself when selecting an empty quickslot * The Held Block has been moved to the lower right corner