Extract common workflow steps to set up build environment

[yuxiang-zhang]

Description

Many workflow files share the same set of steps to set up the build environment. Every update in these places require making changes to 9 workflows at once. This PR extracts some common steps to a separate composite action.

This PR also remove the now inaccessible Slack notifications posted to Weave Slack channels.

This PR also closes #7491 which bumps actions/cache from 3.3.2 to 4.0.0.

Checklist

• Added tests that cover your change (if possible)
• Added/modified documentation as required (such as the README.md, or the userdocs directory)
• Manually tested
• Made sure the title of the PR is a good description that can go into the release notes
• (Core team) Added labels for change area (e.g. area/nodegroup) and kind (e.g. kind/improvement)

BONUS POINTS checklist: complete for good vibes and maybe prizes?! 🤯

• Backfilled missing tests for code in same general area 🎉
• Refactored something and made the world a better place 🌟

[a-hilaly]

Great stuff, thank you!