Generate Loki Quickstart tutorial from documentation source

[jdbaldry]

Uses the source in https://github.com/grafana/loki/pull/13234 to generate the Killercoda tutorial

TODO:

• [ ] Add workflow for regeneration
• [ ] Support generating multiple tutorials
• [ ] Test with other tutorials
• Features
  • [x] Link transformer
  • [x] Version substitution
  • [x] hostname
  • [x] localhost special case
  • [ ] Heading fixer (ensure proper heading hierarchy)
  • [ ] Shortcode transformer
  • [x] figure
  • [ ] note
  • [x] Directives
  • [x] Introduction
  • [x] Ignore
  • [x] Execute
  • [x] Copy
  • [ ] Finish