This removes `ProcState` and replaces it with a new `CliFactory` which
initializes our "service structs" on demand. This isn't a performance
improvement at the moment for `deno run`, but might unlock performance
improvements in the future.
Creating the node_modules folder when the packages are already
downloaded can take a bit of time and not knowing what is going on can
be confusing. It's better to show a progress bar.
