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/migration-guide/v8.x-v9.x/_index.md

@@ -1,4 +1,6 @@
 ---
+title: Migrate plugins from Grafana version 8.x to 9.x
+menuTitle: v8.x to v9.x
 description: Guide for migrating plugins from Grafana v8.x to v9.x
 keywords:
   - grafana
@@ -6,8 +8,6 @@ keywords:
   - migration
   - plugin
   - documentation
-title: Migrate plugins from Grafana version 8.x to 9.x
-menutitle: v8.x to v9.x
 weight: 2300
 ---
 
@@ -73,7 +73,7 @@ We have removed the deprecated `getFormStyles` function from [grafana-ui](https:
 
 ### `/api/ds/query` replaces `/api/tsdb/query`
 
-We have removed the deprecated `/api/tsdb/query` metrics endpoint. Use [/api/ds/query]({{< relref "../../../http_api/data_source/#query-a-data-source" >}}) instead.
+We have removed the deprecated `/api/tsdb/query` metrics endpoint. Use [/api/ds/query]({{< relref "../../../http_api/data_source#query-a-data-source" >}}) instead.
 
 ### `selectOptionInTest` has been removed