Render README for local packages in PM UI

[jgonz120]

Bug

Fixes: https://github.com/NuGet/Home/issues/12583

Regression? Last working version:

Description

Added functionality in the PM UI to render the ReadMe for the selected package. Currently the ReadMe only renders the ReadMe for items which are available on the user's machine.

PR Checklist

• [x] PR has a meaningful title

• [x] PR has a linked issue.

• [x] Described changes

• Tests

  • [x] Automated tests added
  • OR
  • [ ] Test exception
  • OR
  • [ ] N/A

• Documentation

  • [ ] Documentation PR or issue filled
  • OR
  • [ ] N/A

[zivkan]

not so much 🤣

[jgonz120]

I'm going to break this PR down into smaller PRs 😅