Additional indexes for /account/balance endpoint performance improvement

[Kartiiyer12]

CREATE INDEX CONCURRENTLY idx_tx_input_lookup
ON tx_input(tx_hash, output_index, spent_at_block);

secondary index add if furhter improvement is needed.

CREATE INDEX CONCURRENTLY idx_address_utxo_owner_addr_block
ON address_utxo(owner_addr, block DESC);