Codespaces & Live Samples for NUnit Docs

Contributing to open source
Streaming on Youtube
It's been a minute so I took some time to spruce up the NUnit Docs process.

  • Updated the docfx-action container we created, to re-use the docfx 2.60.0 preview, which is now distributed as a .NET global tool.
  • Updated that container to be based on the .NET SDK Ubuntu container for much greater simplicity.
  • Updated our dev container to simplify the installation of our JavaScript tools
  • Created a YouTube video to walk through the contribution process using those things: https://www.youtube.com/watch?v=VSJwystllJM&t=217s
  • Added a solution file for real samples and updated docfx to source the samples from that, and added a build process to build & test those examples.
  • Converted several examples to the samples solution, modernizing and fixing them in the process.
Feels good!