Migrate docs from AsciiDoc to Markdown. The preview can be built after
#212557 is merged.
@florent-leborgne please tag reviewers, add the appropriate label(s),
and take this out of draft when you're ready.
Note: More files are deleted than added here because the content from
some files was moved to
[elastic/docs-content](https://github.com/elastic/docs-content).
**What has moved to
[elastic/docs-content](https://github.com/elastic/docs-content)?**
Public-facing narrative and conceptual docs have moved. Most can now be
found under the following directories in the new docs:
- explore-analyze: Discover, Dashboards, Visualizations, Reporting,
Alerting, dev tools...
- deploy-manage: Stack management (Spaces, user management, remote
clusters...)
- troubleshooting: .... troubleshooting pages
**What is staying in the Kibana repo?**
- Reference content (= anything that is or could be auto-generated):
Settings, syntax references
- Release notes
- Developer guide
---------
Co-authored-by: Florent Le Borgne <florent.leborgne@elastic.co>
