Linea Monorepo readme out of date

[m4sterbunny]

Describe the bug

Readme of docs repo and the related infra repos need updating

• Infra repos are out of date: Linea-Besu links to an archived repo --> suggest updating this to current data on Linea-Besu
  (Also useful links at end of file could include link to both docs prod and docs repo to assist contributors)

NB the monorepo readme repo link list is identical across all the linked repos, change 1: change all

• This repo should explain when to use docs in monorepo vs these docs

Steps to reproduce

Out of date data, not bug

Expected behavior

Out of date data, not bug

Link(s)

https://github.com/Consensys/linea-monorepo

[m4sterbunny]

Have touched all the current infra readmes for this:

• updates Readme to link to active repos & minor style fixes linea-monorepo#1869
• make readme current & minor style fixes linea-specification#352
• fixes liveliness of readme linea-tracer#2562
• fixes readme liveliness & minor style tweaks linea-constraints#852