[Subtask]: File upload API can be used with knowledge base name.

[KevinHuSh]

Parent Issue

#345

Detail of Subtask

1. Have a look at api/app/document_app.py
2. Use API-Key to authorize caller, like what to do in api/app/api_app.py
3. Use knowledge base name instead of kb_id to identify knowledgebase since the name is guaranteed unique.

Describe implementation you've considered

No response