The `core-js` dependency is no longer included in `package.json` for
`cli`-type examples, but only for the `systemjs` ones. This commit
updates the `package.json` templates to reflect that (and also updates
the `npm-packages` guide accordingly).
PR Close#36143
Previously, the `package.json` files added as boilerplate to docs
example projects of type `systemjs` were incorrect/outdated. They
contained unused dependencies and npm scripts and omitted used
dependencies.
This is not a big issue, because these examples are not offered as live
StackBlitz examples or downloadable ZIP archives, but having incorrect
`package.json` files is confusing and makes it more complicated to
update these examples.
This commit updates the `package.json` templates for the `systemjs` docs
examples and other configuration files to include used dependencies (and
remove unused ones). It also removes unused npm scripts.
PR Close#36015