`valohai.yaml` Autocompletion: Schemas & Instructions

[teroyks]

Sort out things needed for using autocompletion when editing valohai.yaml.

• Demo was presented at Skunk week (@teroyks)
• Convert schema YAML files to JSON (Tero has a Makefile update for it)
• Decide on where to put the files
• Decide on how to update the files
• Write instructions for users
  • VS Code is sufficient as a first step
  • Link to the published base schema (either in user/workspace settings or directly in the file)