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/whatsnew/whats-new-in-v3-1.md

@@ -2,13 +2,8 @@
 title = "What's new in Grafana v3.1"
 description = "Feature and improvement highlights for Grafana v3.1"
 keywords = ["grafana", "new", "documentation", "3.1", "release notes"]
-type = "docs"
 aliases = ["/docs/grafana/latest/guides/whats-new-in-v3-1/"]
-[menu.docs]
-name = "Version 3.1"
-identifier = "v3.1"
-parent = "whatsnew"
-weight = 5
+weight = -6
 +++
 
 # What's new in Grafana v3.1