Refactor to npm-utils (#37555)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/37555

Changelog: [Internal] Refactor some npm commands and centralize in npm-utils.

For now, centralize `getPackageVersionStrByTag` and `publishPackage` and update:
1. `publish-npm` to use utilities. This is how we publish `react-native` for commitlies, releases, and nightlies
2. Update `find-and-publish-all-bumped-packages.js` where we publish our monorepo dependencies

Reviewed By: cortinico, hoxyq

Differential Revision: D46131120

fbshipit-source-id: e6020058eb94b4f8d95068b8cd87cc765711be5b