Support User Path Expansion

Wondering if we want to support User Path expansion for the `SSH` related `env` variables.
This would enable the `env` to use things like `SSH_CONFIG_LOCATION="~/.ssh/config"`

Probably just requires wrapping the use of those variables in the python code with `os.path.expanduser`. Not sure if this creates any unintended side effects, or if will work well cross platform.

Open Question: Where does WSL store it's ssh config. All that really matters is that the publickey is read from the correct place, and that VSCode or other SSH client looks at the correct file.