Define new Studio services and improve the tests coverage

Base on the tests driven approach, write the tests using the "given/when/then" approach and the services needed for these tests.
The test cases to cover are :

• I want to get the list of StudioPackage for a user or a Studio project
• I want to manage the features of a Studio project
• I want to manage a Studio project
• I want to version my work in a Studio project