Publish IDL on chain

[KartikSoneji]

Anchor allows publishing the IDL for programs on-chain: https://book.anchor-lang.com/anchor_references/cli.html#idl
Publishing the IDL for gem bank, gem farm and other programs will make them easier to fetch in other apps, and also allow blockchain explorers like explorer.solana.com to automatically deserialize and display the accounts and instructions in a more readable format, making debugging much easier.