Deprecate MergeReadiness

[wackerow]

Description

• Removes notifications related to The Merge
• Removes MergeReadiness checklist page
• Moves pertinent information from this page to corresponding places in the existing FAQ and Checklist pages
• This includes information related to setting up a JWT and fee recipient
• Adds client-diversity notice to Lighthouse page
• Updates copy to be correct in a post-merge environment
• Updates notes about Shanghai to inform that withdrawal functionality is proposed to be included in this upgrade. Removing stating inclusion as fact until further decisions have been made regarding this upgrade.

Preview deploy:
https://deploy-preview-557--serene-carson-3331d5.netlify.app/en/checklist

[wackerow]

Added a few commits to clean up some of the links... original used the name of the document from each client docs page like "Configure Fee Recipient" but this ended up being redundant, and would just add to the number of strings that need to be translated.

I removed these labels, pulled any client specific links into the clientInfo object, and render these links as just pipe-separated inline lists, adding some text in front of each to identify the type of doc.

[hwwhww]

Great work! It's not just deprecating the merge checklist but also some thoughtful proofreading work. 👍