docs: add general coverage page

[itaysk]

Description

added a high-level doc that shows a growing list of supported languages and platforms. This is not supposed to be the complete supportability matrix, but a landing page that can give a quick hint if we support X or not, and if so, where to find the full details.

Let me know if you think it's helpful

[AnaisUrlichs]

I think this is good since many people don't read beyond the getting started -- do you think a list is better readable than a table?
Somewhat independent of this PR, I am worried that we keep adding things to make the docs more readable and through that duplicating sections e.g. we have to make sure the list will stay up to date in addition to the table https://aquasecurity.github.io/trivy/v0.38/docs/vulnerability/detection/language/

[itaysk]

do you think a list is better readable than a table?

if we want to add more columns then we'd need a table, but the motivation of this page was to simplify the existing tables.

we have to make sure the list will stay up to date in addition to the table

yes there's no new information in this page. it is a summarization of existing information to have a single link we can send everyone asking "does trivy support X language" to. If they want a quick go/no-go they'll find the answer here. If they want to dive deeper they can read the detailed tables which are linked to from here

[knqyf263]

Conflicting now

[itaysk]

fixed