Docs: Link to architecture docs from Developer guide (#19778)

* Link to architecture docs from Developer guide

* Fix link

contribute/architecture/README.md

+# Architecture
+
+Are you looking to take on contributions with bigger impact? These guides help you get a better understanding of the structure and design of the Grafana codebase.
+
+Learn more about the backend architecture:
+
+- Part 1: [Services](services.md) 
+- Part 2: [Communication](communication.md)
+

contribute/developer-guide.md

@@ -193,8 +193,9 @@ find ./conf ./pkg ./public/views | wc -l
 
 Another alternative is to limit the files being watched. The directories that are watched for changes are listed in the `.bra.toml` file in the root directory. 
 
-## Learn more
+## Next steps
 
-- Read our [style guides](/contribute/style-guides).
-- Learn how to [Create a pull request](/contribute/pull-request.md).
-- Read [How to contribute to Grafana as a junior dev](https://medium.com/@ivanahuckova/how-to-contribute-to-grafana-as-junior-dev-c01fe3064502) by [Ivana Huckova](https://medium.com/@ivanahuckova).
+- [Create a pull request](/contribute/pull-request.md)
+- [Style guides](/contribute/style-guides)
+- [Architecture](architecture)
+- [How to contribute to Grafana as a junior dev](https://medium.com/@ivanahuckova/how-to-contribute-to-grafana-as-junior-dev-c01fe3064502)