[pt] Carefully setup fallback pages for /pt/ecosystem

[chalin]

Originally posted by @chalin in #6261 (comment):

The fallback pages (English version) for /ecosystem/ aren't working like currently happens on pages under /docs/, am I missing something? Do I need to set any other config or something like that?

Preview: https://deploy-preview-6261--opentelemetry.netlify.app/pt/ecosystem/

Hi @vitorvasc - that's because we haven't setup fallback pages for that section yet. It will need to be done with care because I would (ideally) like to avoid duplicating the registry entries because there are too many and they get updated too often. Would that be ok with you? If so, I'll look into it as soon as I can (today or tomorrow).