Environment manager should suggest unique folder names

[bhavyaus]

Testing #458

While testing the Auto-Create environment step, I was asked to enter a name for the virtual environement with .venv auto suggested. Accepting this suggestion causes:

[cwebster-99]

A user should be able to go through Quick Create multiple times, we should check the code in this scenario so that if they already have a .venv to suffix the with a number (i.e. .venv1)