Adds a topic that describes how to fork a repo to update it.

Content that is now reused is moved to `inc`lude files.

Change title of topic about updating an older module to `Porting` to distinguish from new topic.

Fix link to reference architecture template

Adds a topic that describes how to fork a repo to update it.

Content that is now reused is moved to `inc`lude files.

Change title of topic about updating an older module to `Porting` to distinguish from new topic.

…entation into fork-support

- Recombine creating and updating a module as before
- Update dev setup and migrate-module to support forks
- Remove unused include files