ContentTypeQuery does not extend BaseQuery

[jedabero]

Unlike GlobalFieldQuery and Entries, ContentTypeQuery does not extend BaseQuery.

We've been doing a workaround to be able to use pagination:

const stack = contentstack.stack(stackConfig):

const contentTypeQuery = stack.contentType():

contentTypeQuery._queryParams = { ...contentTypeQuery._queryParams, skip: 10, limit: 10 };

const { content_types } = await contentTypeQuery.find()

So I created the following PR which should hopefully expose the base-query and pagination methods for ContentTypeQuery

#332