Release Darken Depths beta-1.20.2-1.2.0

"Implement Shadow Inventory and Tag Support for Items"

Extend functionality of ShadowStoneItem and add a custom inventory ShadowStoneInventory. Also, added DarkenDepthsItemTag file that provides tag support for darken depth items. For managing these changes, ShadowCoreItem is added and Armor changing function is removed from ShadowStoneItem, as now it supports custom inventory. The ShadowStoneInventory read and write NBT data, which is necessary to persist the inventory across sessions. Made additional changes in PlayerEntityMixin to support custom inventory opening and item saving. Version is updated to reflect these substantial changes.ing"