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.
This lazily does an "npm install" when any package name matches what's
found in the package.json or when running a script from package.json
with deno task.
Part of #17916
Closes #17928
This is a super basic initial implementation. We don't create a
`node_modules/.bin` folder at the moment and add it to the PATH like we
should which is necessary to make command name resolution in the
subprocess work properly (ex. you run a script that launches another
script that then tries to launch an "npx command"... this won't work
atm).
Closes #17492
