Add configurable rate limiting. The threat scenario this protects against is the following.

• Suppose 1_000_000 WETH has been transferred from Ethereum to Cosmos Hub, so that 1_000_000 WETH is locked in escrow.
• Suppose an attacker has the power to generate malicious proofs (for ex. an SP1 vulnerability).

Then without rate limits, the attacker can:

1. Generate a malicious proof that a user has sent 500_000 WETH back from Cosmos Hub to themselves.
2. The attacker receives the funds and runs.

With a rate limit of 100_000 ETH:

1. The attacker must generate a malicious proof for a packet of size at most 100_000 ETH.
2. Once the rate limit has been hit, the pauser notices the discrepancy between Cosmos Hub and Ethereum, and pauses transfers.