Add direct links to the download pages

[damienalexandre]

Downloading Elasticsearch when coming from organic search or https://www.elastic.co/ homepage is more and more difficult; there is no direct link to the Elasticsearch download page.

We could provide them.

[rahuldkjain]

Hi @damienalexandre I would love to add the direct download links. Please assign this issue to me.

[pyrech]

Hey @rahuldkjain. Go for it 😉

Could you do it for all versions? Thanks 🙂

[rahuldkjain]

@pyrech Could you please explain how it needs to be done for all versions?

[rahuldkjain]

@damienalexandre @pyrech Please review the PR #26