Add new rmrk-ui-react package for drop-in components

[Yuripetusko]

Add a new package called rmrk-ui-react with a collection of drop-in components similar to existing nft-renderer. Example for first components to add:

• NFT media display
• Inventory display (renders all inventory items)
• Inventory management controls
• Pending nfts component (with accept and reject buttons)
• Pending asset component (with accept and reject buttons)