[Tech Docs December Launch] TRs for Milestone 1 - deprecations and upgrade notes

Context

There has been some confusion and back and forth on the translateability as well as the process on getting these pages translated. Conversations have happened here:

• gitlab-org/gitlab!207491 (merged)
• "Hide" Versions Menu from translation and its n... (#532 - closed)
• Decision of how to proceed has been documented:
  • Here Ignored paths for tech docs JA launch (#137)
  • #532 (comment 2807027052)

Translation request scope

• https://docs.gitlab.com/update/versions/ and all its nested pages, so:
  • https://docs.gitlab.com/update/versions/gitlab_18_changes/
  • https://docs.gitlab.com/update/versions/gitlab_17_changes/
  • https://docs.gitlab.com/update/versions/gitlab_16_changes/
  • https://docs.gitlab.com/update/versions/gitlab_15_changes/
  • https://docs.gitlab.com/charts/releases/
  • https://docs.gitlab.com/charts/releases/9_0/
  • https://docs.gitlab.com/charts/releases/8_0/
  • https://docs.gitlab.com/update/background_migrations/
• https://docs.gitlab.com/update/deprecations/
• https://docs.gitlab.com/update/breaking_windows/
• https://docs.gitlab.com/update/terminology/

To-do

• Check if the files are translated already and/or updated on the source
• Trace back if they were ever merged