Export all public classes

[parkerduckworth]

Make all public classes in submodules importable from client entrypoint.

This allows the following syntax:

import weaviate, { ObjectsBatcher } from 'weaviate-ts-client';

Rather than having to do:

import weaviate from 'weaviate-ts-client';
import ObjectsBatcher from 'weaviate-ts-client/types/batch/objectsBatcher';

etc.