env settings

Allow adding environment variables in VSCode-Anywhere.

A simple example, in the vscode-anywhere.sls file to ask to add some variables in the env file in python3module :

vscode-anywhere:
    python3:
        enabled: True
        env:
            PATH: /mypath/bin
            PYTHONPATH: /mypythonpath/lib

PATH variable is a specific variable that appends in this case/mypath/bin to the PATH variable. Other variables will be replaced. PYTHONPATH will be set to /mypythonpath/lib.