Deprecate packages for v10

[joshblack]

We are deprecating two packages in preference of upstream versions in Carbon Elements. This issue is to track updating the repo README to include the deprecation notice and linking to migration guides, alongside deprecating the packages themselves.

• carbon-icons
  • Update repo README docs(project): add deprecation notice carbon-icons#99
  • Deprecate npm package
  • Archive repo
• carbon-themes
  • Update repo README Update README.md carbon-themes#38
  • Deprecate npm package
  • Archive repo

[shinytoyrobots]

This is a task specific to do today on release, yes?

[stale]

We've marked this issue as stale because there hasn't been any activity for a couple of weeks. If there's no further activity on this issue in the next three days then we'll close it. Thanks for your contributions.

[stale]

As there's been no activity since this issue was marked as stale, we are auto-closing it.