feat: add support for non-app dir as Workspace root dir

[Abadulrehman]

A potential solution for #2. Introduces a new setting, workspaceRoot, which can be one of [single-app, apps, bench], with "single-app" being the default and resulting in no change in the behavior.

Selecting one of the other settings takes them into account when forming the path of the test.

[Abadulrehman]

@ankush Have a look and see what you think. This works very well for my use-case now.

[TomasBarry]

@ankush - is there any chance of this being merged in? 🙌