Added tutorial on advanced configuration

- Covers all the various ways to manipulate configuration, including the order in which
  configuration is merged.
- Added information on the configMerge event to the module manager chapter, linking it to the
  tutorial.
Incorporate feedback

- from @superdweebie
Modified config tutorial for master

- Removed references to configMerge event
Incorporated feedback

- fixed a heading
Merge branch 'hotfix/#904'

Close #904