[i18n] Factor prose out of shortcodes like `docs/latest-release`

[chalin]

This idea is to separate concerns, and put prose in includes files and code in shortcodes.

Context:

• #6337 and other non-en languages
• https://deploy-preview-6337--opentelemetry.netlify.app/ja/docs/collector/distributions/

  

  Which is solved by #6506

Tasks

• [x] #6476
• [x] #6494
• [x] #6506
• [x] #6581
• [x] #6583
• [x] languages/index-intro:
  • [x] en - #6750
  • [x] pt - #6751
  • [x] ja - #6753
• [x] #6814
• [x] Cleanup & prep before making further changes:
  • [x] #6821
  • [x] #6822
• [x] More cleanup:
  • [x] #6829
  • [x] #6836
  • [x] #6941
• [ ] languages/resources-intro.md
  • [x] en
    • [x] #6816
    • [x] #6824
  • [x] pt - #6829 by @vitorvasc
  • [x] ja - #6840
• [ ] Consider moving content/en/docs/_includes/exporters/intro.md to be under docs/languages/_includes, and using an absolution site-specific path in the shortcode.
• [ ] ...

Related:

• [ ] Eliminate no-duplicate-heading exception from pages like exporters

[Msksgm]

@chalin

I think that the below issue is solved in https://github.com/open-telemetry/opentelemetry.io/pull/6506. Then, I mentioned this issue in the PR.

https://deploy-preview-6337--opentelemetry.netlify.app/ja/docs/collector/distributions/

[svrnm]

@chalin how's the status on that, most TODOs are checked, can this be closed or is there much more missing?