Docs: updates for file-based menu (#28500)

* initial

* cleanup

* remove bad aliases

* cleanup, fix links

* add docs-file-based-command

* update docs

* update readme

* fix broken links

* fix spelling

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>

docs/sources/panels/visualizations/stat-panel.md

@@ -2,7 +2,6 @@
 title = "Stat panel"
 description = "Stat panel documentation"
 keywords = ["grafana", "docs", "stat panel"]
-type = "docs"
 aliases = ["/docs/grafana/latest/features/panels/stat/", "/docs/grafana/latest/features/panels/singlestat/", "/docs/grafana/latest/reference/singlestat/"]
 weight = 900
 +++