[FEA] more docs, image cleanup, module renames

[trxcllnt]

• Rename modules @nvidia/ -> @rapidsai/.
• Keep VSCode Remote Containers server in .vscode/server in the workspace.
• Add fixguid to the devel container so it can be launched w/ a different UID than it was built with.
• Move the .cache dir up one level so we can do COPY modules modules in the build
• Remove the source + build after npm pack to reduce the intermediate packaging container image size.
• Split out the merge PR github action into separate jobs to maximize concurrency in CI, add custom image builder action to reduce duplication.
• Fix image tags to remove extra -:

  - ghcr.io/rapidsai/node:21.12.00-runtime-node-16.10.0-cudagl11.4.2-ubuntu20.04-main-amd64
  + ghcr.io/rapidsai/node:21.12.00-runtime-node16.10.0-cudagl11.4.2-ubuntu20.04-main-amd64

• Add more docs on:
  • Setting up a local development environment
  • Starting and connecting to the devel container from VSCode
  • Which images are available from the github container registry
  • How to use and/or extend the runtime images for app code
  • Launching the preinstalled demos in the demos container

[nicolasgere]

Do we know when a package would be publish? We would like to try this package to replace our headless-gl setup