refs: https://github.com/TryGhost/Toolbox/issues/147
Correctly prepares the stack when wrapping another error, and adds a new method on errors to create an error which can be shown to the user (i.e. remove the stack trace in production)
refs #9178
- first iteration of tidying up the unit tests
- this is useful in the current stage, because if i move files in the server folder, i need a clean folder/file structure to detect which tests needs to move
- this is a simple cleanup to reflect the current server folder structure
