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/developers/plugins/backend/_index.md

@@ -1,7 +1,6 @@
 +++
 title = "Backend plugins"
 keywords = ["grafana", "plugins", "backend", "plugin", "backend-plugins", "documentation"]
-type = "docs"
 aliases = ["/docs/grafana/latest/plugins/developing/backend-plugins-guide/"]
 +++
 

docs/sources/developers/plugins/backend/grafana-plugin-sdk-for-go.md

@@ -1,7 +1,6 @@
 +++
 title = "Grafana Plugin SDK for Go"
 keywords = ["grafana", "plugins", "backend", "plugin", "backend-plugins", "sdk", "documentation"]
-type = "docs"
 +++
 
 # Grafana plugin SDK for Go

docs/sources/developers/plugins/backend/plugin-protocol.md

@@ -1,7 +1,6 @@
 +++
 title = "Plugin protocol"
 keywords = ["grafana", "plugins", "backend", "plugin", "backend-plugins", "documentation"]
-type = "docs"
 +++
 
 # Plugin protocol