Wallet Labels

[cryptoquick]

• All transfer methods should accept an optional argument for a transaction label for every transaction made.
• We should keep separate files for BTC, LN, and RGB transactions, and update these files as transactions are made.
• These should be a HashMap<Txid, String> (a HashMap keyed by transaction ids and with values as label strings) so they can be looked up by transaction history information, serialized in Postcard format, and persisted in Carbonado.
• For L1, we should also have a method for exporting in BIP-329 as JSON.
• Finally, we need to return this data on get_wallet_data (L1), list_transfers (RGB), and get_txs (LN), and modify existing structs