Bootstrapping heist minions with salt extensions is inconvenient. It would be very useful to have a CLI option to specify a list of extensions to install before a minion is started A more flexible approach: - pre-flight shell/powershell script (can be used to install/cleanup any required stuff, not just extensions, the critical part is that a pre-flight script should be run after the minion is unpacked) - an option to pass environment variables to a remote end (to control the pre-flight script and also pass the vars to the minion) Example scenarios: - a generic pre-flight script installs extensions that are defined in SALT_EXTENSIONS env var - pass a modified PATH or PYTHONPATH variable to a Heist minion (to locate some custom executables or modules, the benefit is that extensions and binaries can be cached this way outside of the temporary heist dir)