When a step of the create-project command fails, the script must not continue

[omarlopesino]

Currently, when the project is installed by composer create-project, if there is a temporary error in the project creation. The script does continue.

Example: Currently, if site-install fails, the script continues and the output is 'Congratulations'.

I propose to catch the error, warn the user, and then erase the project created to prevent the project half-installed and inconsistent. Alternative solutions are welcome.