Merge branch 'jarv/readiness-review-update' into 'master'

Adds references to the new Readiness Review process for Infrastructure

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/129773



Merged-by: Michele Bursi <mbursi@gitlab.com>
Approved-by: Rachel Nienaber <rnienaber@gitlab.com>
Approved-by: Michele Bursi <mbursi@gitlab.com>
Approved-by: Alan Richards <arichards@gitlab.com>
Approved-by: Dave Smith <dsmith@gitlab.com>
Co-authored-by: John Jarvis <jarv@gitlab.com>