Docs: Plugins doc reorganization, part 1 (#69864)

* Initial commit

* Prettier fixes

* Doc-validator fixes part 1

* Doc-validator fixes part 2

* More doc-validator fixes

* More doc-validator fixes

* Test

* link test

* Linnk test

* Link test

* More fixes

* More fixes

* Doc-validator fixes

* Doc-validator fixes

* fix broken link

* Fix

* Testing

* Doc fixes

* Link fixes

* Fix links

* Update docs/sources/developers/plugins/create-a-grafana-plugin/_index.md

Co-authored-by: David Harris <david.harris@grafana.com>

* Testing

* Testing

* Testing

* Testing

* Doc-validator fixes

* Doc-validator fixes

* Doc-validator fixes

* Fix broken links for plugins reorganization project

* Prettier fixes

* Prettier fixes

* Incorporate reviewer feedback

* Link fixes

* Link fixes

* Link fixes

* Link fix

* Deleted space

* Codeowners fix

* Change grafana.com links to absolute URLs for Hugo

---------

Co-authored-by: David Harris <david.harris@grafana.com>

docs/sources/developers/plugins/legacy/style-guide.md

@@ -1,7 +1,8 @@
 ---
+title: Legacy code style guide
 aliases:
   - ../../../plugins/developing/code-styleguide/
-title: Legacy code style guide
+description: Deprecated guide for Angular plugin development.
 ---
 
 # Legacy code style guide
@@ -27,7 +28,7 @@ grafana-piechart-panel
 mtanda-histogram-panel
 ```
 
-For more information about the file format for `plugin.json` file, refer to [metadata]({{< relref "../metadata/" >}}).
+For more information about the file format for `plugin.json` file, refer to [metadata]({{< relref "../metadata.md" >}}).
 
 Minimal plugin.json: