Implement batching multiple UTXOs to a single UTXO consolidation logic transaction

[soju-drinker]

Description

When a deposit transaction is picked up from the reveal service during polling, there needs to be a secondary tx initiated by the stackers that consolidates the currently existing UTXO in the peg wallet with the deposit UTXO. This can be generalized into a batching transaction that consolidates multiple deposit UTXOs + peg UTXO into one UTXO in a single transaction.

Context / Purpose

Our peg wallet design necessitates only one UTXO at all times, as detailed in this document. This issue actually implements the mechanism to achieve that

Steps

1. Generate a new BTC tx consolidating all the polled deposits or (a max limit number) whichever is lower
2. If not all polled UTXOs were batched in step 1, repeat step 1 multiple times when the first transaction is in the pending mempool in BTC

Artifacts / Acceptance Criteria

• Consolidation TXs are generated successfully
• Multiple consolidation TXs are generated in succession in a chain and work as intended
• Smoke tests testing the above scenarios