Add instructions for pip installation to the docs

[WeirAE]

Synopsis

Land-DA and JEDI users have requested the ability to install UW into their environments . @maddenp-noaa kindly wrote this pip installation that I have converted to text for the user installation guide.

Type

• Bug fix (corrects a known issue)
• Code maintenance (refactoring, etc. without behavior change)
• Documentation
• Enhancement (adds new functionality)
• Tooling (CI, code-quality, packaging, revision-control, etc.)

Impact

• This is a breaking change (changes existing functionality)
• This is a non-breaking change (existing functionality continues to work as expected)

Checklist

• I have added myself and any co-authors to the PR's Assignees list.
• I have reviewed the documentation and have made any updates necessitated by this change.

[maddenp-noaa]

That format-check failure in CI is not your fault. I made a change to condev recently to conform to Python-community preferred style for package specs, which uses == for pinning to a specific package version instead of =. You can either revert the change to recipe/meta.json in your PR/branch, or just leave this as-is and I'll force-merge the PR for you when it's approved.

[WeirAE]

Ah thanks, I was trying to track that one down - I'm inclined to leave it as-is if you can do the force

[maddenp-noaa]

I said in Conversation chain that I can merge this for you even with the formatting-check failure in CI, but you should probably revert the changes to recipe/meta.json so that those pass. I'll fix this for everybody today.

[maddenp-noaa]

Ugh, now you're hitting the issue with the gnu.org HTTP failure in the docs. Also not your fault, and nothing to can do to fix it. I'll go ahead and merge this PR and if there's anything left to fix, I'll do it in a branch I'm about to merge.

Thanks for adding this to the docs!