* Script is written to filesystem, not inlined as argument
* Pass script either as string, or directory+filename
Signed-off-by: Solomon Hykes <solomon@dagger.io>
* `cmd` is renamed to `command` for readability
* `script` is removed. Feature moves up the stack (bash.#Run,
python.#Run)
Signed-off-by: Solomon Hykes <solomon@dagger.io>