Follow up on restructuring the APIs in modules

[ftomassetti]

I noticed two things after #29 was merged:

• it seems there is this empty file left: https://github.com/LionWeb-io/lionweb-repository/blob/main/packages/core/src/controllers/LionWebBulkApiWorker.ts
• We may need to update the README to reflect on the changes

[joswarmer]

Oops, this file should have been removed.

[joswarmer]

Fixed in latest PR