Project duplication should use the suffix "-2" instead of " [2]"

Because a validation was inserted to only allow only letters (A to Z), digits (0 to 9), underscores (_), dots (.) or dashes in the project name, the suffix for a new project (duplicated or imported project) with same name as another one should use the pattern "-2", "-3" and so on, instead of " [2]", " [3]" and so on.