Rethink mandatory package.json property strategy

As a library maintainer that adds bob to an existing project, you will run bob build multiple times until you fixed all the errors it throws at you.

It might make sense to solve this by either

1. have an onboarding command, which adds/updates all the required package.json entries
2. have an "easy" mode, that adds the required package.json entries only in the dist/package.json file