docs: add support mariadb-vector capabilities

[seulement55]

Update documents for open-webui/open-webui#21931

[pr-validator-bot]

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[seulement55]

The documentation has been updated in #1137, so I will close this PR as well.

[Classic298]

Hi @seulement55 I added some env vars already, mind rebasing this? I will happily merge it then for the other modified pages

[seulement55]

hi @Classic298

Thank you, I’ll rebase it shortly.

[Classic298]

Awesome thanks