[TASK] Make use of `TimeLag` Middleware for safety against reorgs on EVM Chains

[shekohex]

Overview

We currently have block-confirmations in the configurations, but we recently removed the usage of this intuitively in #501 What we should do instead wrap that into ethers::middleware::timelag::TimeLag instead and use the configured value of block-confirmations here. So that by default, everything is lagged by this number of blocks.

Notice that, even the latest_block_number will be lagged by the block-confirmations here. We shall decide wisely which parts may need this features and which parts isn't.

Task Checklist

• [ ] Change our type EthersClient to be wrapped TimeLag middleware.
• [ ] Update tests
• [ ] Update docs.

[salman01zp]

Adding TimeLagmiddleware for the following features.

• Event Watchers ✅
• Event Handlers ✅
• Tx-queue ✅
• Tx-relay ❌