Clarity Deposit Function

[setzeus]

1. Summary

This issue is a kickoff issue related to #56. Here we'll implement the only two functions signers will call to complete a deposit: 'deposit-accept' & 'deposit-accept-many.'

2. Context & Purpose

The purpose of this issue is to successfully implement the most critical functions for depositing into the sBTC protocol. Called by the bootstrap signer set, the 'deposit-accept' functions result in a user (specific in payload) receiving some amount of sBTC.

3. Deliverables

• Implement 'deposit-accept' function
• Implement 'deposit-accept-many' function

[setzeus]

The main 'complete-deposit-wrapper' function is already included, now working on the 'many' variation.