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/datasources/postgres.md

@@ -2,11 +2,7 @@
 title = "PostgreSQL"
 description = "Guide for using PostgreSQL in Grafana"
 keywords = ["grafana", "postgresql", "guide"]
-type = "docs"
 aliases = ["/docs/grafana/latest/features/datasources/postgres/"]
-[menu.docs]
-name = "PostgreSQL"
-parent = "datasources"
 weight = 1200
 +++