New API Proposal - Knowledge Base - Manage (from "MaaS" API family)

[lihaojie-CMCC]

Proposal to create a "Knowledge Base - Manage" API:

This API supports users in building and managing knowledge bases, including the creation, updating, querying, modification, and publication of the knowledge base.

This API constructs the knowledge base based on the knowledge provided by users (including doc/pdf/txt/csv), which can be utilized by Q&A assistants.

This API provides services for users who need to build a knowledge base.

Related to #84