This partially reverts commit 51e56f994c.
Ignoring plug'n'play, it looks like yarn and pnpm do get the
filesystem layout right for this scenario, which is good news.
It also looks like npm 10 will get it right too.
- Remove all custom download logic for prebuilt binaries
- Add scripts to populate package contents
- Specify minimum versions of common package managers
- Remove sharp.vendor runtime API as no-longer relevant
- Update installation docs and issue templates