Add a new scenario to test basic forking functionalities

This will automatize the Forking part of https://docs.google.com/spreadsheets/d/15AtBb6s2p_HvtUe5G9GUSc2ngt69X8dO-418zMuT4us/edit?ts=5b07999b#gid=0.

Steps:

1. Log-in with root
2. Create a public project (we already have a factory for that)
3. Sign-out
4. Sign-up with a new user
5. Fork the project created in 2.
6. Clone the fork's repo and push changes to the fork's repo (we already have a factory for that)
7. Submit a merge request to the origin project (we already have a factory for that)
8. Sign-out
9. Log-in with root
10. Accept the merge request