Features Needed After Sepolia Upgrade

[rauljordan]

This PR fixes a few items discovered after the Sepolia upgrade for BoLD

• Support custom withdrawal address as a flag, defaulting to the txOpts.From if not specified
• Support auto-deposit and auto-increase-allowance flags that run on startup if potential staker does not have enough deposit and/or allowance to participate
• Add an option to call newStake on startup, disabled by default. Helps delegated stakers perform their duties

The auto-deposit feature occurs each time we make a move involving the stake token. There are three instances of this:

• Opening a new stake on an assertion
• Creating a block-challenge root edge
• Creating a subchallenge root edge

We check the stake token address has code to ensure it is a valid contract

[eljobe]

LGTM