Angular Package Format v6 stops bundling files in the esm5 and esm2015
directories, now that Webpack 4 can tree-shake per-file.
Adds some missing files like package.json to make packages closer to
what we publish today.
Refactor ng_package to be a type of npm_package and re-use the packaging
action from that rule.
PR Close#22782
This helps ensure we use the same tsconfig.json file for all compilations.
Next steps are to make it the same tsconfig.json file used by the editor
PR Close#20964
Alex Eagle
Misko Hevery