### What problem does this PR solve?
Consolidate "set_meta" API into "update_document" .
Before consolidation
Web API: POST /api/v1/document/set_meta
Http API - PUT /v1/datasets/<dataset_id>/document/<document_id>
After consolidation, Restful API -- PUT
/v1/datasets/<dataset_id>/document/<document_id>
### Type of change
- [x] Refactoring