Add links to Microsoft Learn resources for System app (#558)

<!-- Thank you for submitting a Pull Request. If you're new to
contributing to BCApps please read our pull request guideline below
* https://github.com/microsoft/BCApps/Contributing.md
-->
#### Summary <!-- Provide a general summary of your changes -->
Enhanced information to the repo documentation

#### Work Item(s) <!-- Add the issue number here after the #. The issue
needs to be open and approved. Submitting PRs with no linked issues or
unapproved issues is highly discouraged. -->
Fixes #557







Fixes
[AB#500610](https://dynamicssmb2.visualstudio.com/1fcb79e7-ab07-432a-a3c6-6cf5a88ba4a5/_workitems/edit/500610)

---------

Co-authored-by: Marcus Nordlund <[email protected]>
Co-authored-by: Natalie Karolak <[email protected]>
Co-authored-by: Alexander Holstrup <[email protected]>

CONTRIBUTING.md

@@ -66,6 +66,17 @@ If you would like to add new capabilities to the product as described in **B)**,
 
     Once the issue is created on GitHub, it still needs to be approved. Once approved, the rest of the process is identical to the process described in **A)**.
 
+## Get to Know the System App
+
+Before updating the System Application, familiarize yourself with the following sites on Microsoft Learn:
+
+- [Module architecture](https://learn.microsoft.com/dynamics365/business-central/dev-itpro/developer/devenv-blueprint)
+- [Get started with modules](https://learn.microsoft.com/dynamics365/business-central/dev-itpro/developer/devenv-blueprint)
+- [Set up your development environment](https://learn.microsoft.com/dynamics365/business-central/dev-itpro/developer/devenv-set-up-an-environment)
+- [Create a new module](https://learn.microsoft.com/dynamics365/business-central/dev-itpro/developer/devenv-new-module)
+- [Create a .NET wrapper module](https://learn.microsoft.com/dynamics365/business-central/dev-itpro/developer/devenv-create-a-wrapper-module)
+- [Change a module](https://learn.microsoft.com/dynamics365/business-central/dev-itpro/developer/devenv-change-a-module)
+
 ## More Resources
 * This project has adopted the [Microsoft Open Source Code of Conduct](https://opensource.microsoft.com/codeofconduct/).
 For more information see the [Code of Conduct FAQ](https://opensource.microsoft.com/codeofconduct/faq/)