Adding faultproof-withdrawals monitoring

[raffaele-oplabs]

faultproof-withdrawals replaces chain-mon faultproof-wd-mon.

The functionality is the same as faultproof-wd-mon, but embedded in monitorism.

A clear and concise description of the features you're adding in this pull request.

Tests

Tests are going to be added soon.

Additional context

Add any other context about the problem you're solving.

Metadata

• Fixes #[Link to Issue]

[Ethnical]

Multiples comment has been sent through this first review. We should make sure we are following the correct standard for the name of the files also.

[Ethnical]

We are missing few todos that I will put there to make sure we are aligned or wants to track:

• Comments functions with go-docs standard.
• Update the README global + the README of the faultproof-withdrawals
• clean the code with the current suggestions.
  and then we should be able to merge 🚀
  Hope also the linter will help us to clean the code faster now.

[Ethnical]

If possible to change binding to BINDING.md for markdown.
optimismportal should be OptimismPortal.go
and the file in bindings in uppercase.

[Ethnical]

We conclude that documentation will arrived later on, for this new monitor and some minors improvements for the metrics due to quick need to merge this PR!

[Ethnical]

Let's go 🚀