Examples: add CI workflows

[jwmueller]

Setup CI system (Github Actions) for Examples Repo that can:

• release Colab versions of all notebooks with links to them (like our Tutorials)
• lint notebooks to ensure good formatting, check kernels being used. Example tools to consider may include:
  https://stackoverflow.com/questions/58207645/how-to-use-pylint-or-other-linters-with-jupyter-notebooks
  https://pypi.org/project/julynter/