Update Getting Started Page

[FiannaOBrien]

• [X] Split OSs into individual pages
• [ ] Test install on each OS
• [X] Remove links & text related to to empty "optional dependencies" page
• [ ] Test user experience workflow
• [ ] Split specialty installs into How-To Guide pages

[FiannaOBrien]

I need some information on the binaries page. I can't find a clear reference to this page within the getting started docs and trying to hide the optional dependencies content has removed the binaries page from the TOC tree, causing a meltdown. The binaries page is content-rich, so I don't want to lose it, I just need to know more about what it is, why it is, and where it should be housed to be most useful.

[eslickj]

I have the install testing sort of covered with docker here https://github.com/IDAES/idaes-ext/actions. We can setup GitHub actions to exactly reproduce the docs and use a similar setup maybe. Unfortunately I now have ARM64 linux and macOS builds, to testing those (I guess) requires a Mac VM and a local docker install, but mostly I think we could do the same thing. As far as I know they don't have ARM64 runners hosted by GitHub yet.

I can get you more information on the binaries page. Just let me know what you need. Once I have new binaries ready, I'll need to update it anyway.

[ksbeattie]

@FiannaOBrien, are the above checkboxes done now with the merging of PR #885?