Add clone/duplicate option to env

It would be nice to have the option in environments to clone an existing environment.

At the moment you can't clone environments but often you're going to want the same keys in different envs so adding two options Clone, and Clone without values would be very useful.

Clone; would create a new env with the same keys and values

Clone without values; would create a env with the same keys but default the values to empty read to be populated