This commit allows building angular.io against the locally built Angular
packages. It adds two new npm scripts:
- `setup-local`: Same as `setup`, but overwrites the Angular packages for both
angular.io and the examples boilerplate with the locally built ones.
- `build-local`: Same as `build`, but uses `setup-local` instead of `setup`
under the hood, thus overwriting installed Angular packages with locally built
ones.
Fixes#18611
Georgios Kalpakas