Clarify macOS (OS X) options in download.html

[JDLH]

Clarify the difference between native and VM packages for macOS in download page.

Add a paragraph explaining the difference between native installation and VMs. Clearly announce that VM option does not support M1 (arm64) CPUs. In the macOS title listing the 6 versions, add "native" and "VM" clarification. In each download entry, add "native" and "VM" clarification phrases.

In the System Requirements text, clarify that native installers require x64 or arm64, but that VM requires x64 and does not support arm64.

[beltran-rubo]

Thanks for the suggestions. This is a repo for the static page to make it available via GitHub pages. Those html files have been generated with Middleman tool from https://github.com/ApacheFriends/web repository. It would be great if you implement those changes there, if not I will do my best for updating them when I have a chance. Thanks

[JDLH]

Thank you for the information about the Middleman tool from https://github.com/ApacheFriends/web repository. I am happy to figure out how that tool works, and make this change there. In the meantime, I'll open an issue there to track this requested change.

Will you be able to accept a pull request there, regenerate the static pages, and propagate to the website promptly? Or is it better to apply this PR to the static changes, then override it with changes to the Middleman sources when you have time?

[beltran-rubo]

Thanks for your contribution, we can merge this change to appear into the English website only for now.

Please, when you have time review ApacheFriends/web#16 so we can regenerate the web site for all languages from the source of truth.