add more tests cases for scarb projects

[glihm]

Is your feature request related to a problem? Please describe. The spawn-and-move example is currently too simple. And we miss some use cases like:

1. Compiling a library
2. Compiling a workspace
3. Contracts with same name but not the same path
4. Using external contracts

Describe the solution you'd like We should add more projects into example to break down the cases we're not covering yet. This will help detecting errors during the tests earlier, and some edge cases of Scarb compiler.

Additional context We should add different project to cover specific things, to ensure things can be test easily and separately.