YDB adapter docs

[vgvoleg]

What are you changing in this pull request and why?

We've created a DBT adapter for YDB database
https://github.com/ydb-platform/dbt-ydb
So we are happy to mention it on official docs.

Checklist

• The changes in this PR meet the docs style guide/fundamentals required for all content.
• Applied the proper versioning rules if the content is for specific dbt version(s): (version a whole page or version a block of content
• The content in this PR requires a dbt release note, so I added one to the release notes page.).

[vercel]

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