Add time utils (#10849)

### What problem does this PR solve?

- Add time utilities and unit tests

### Type of change

- [x] Refactoring

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Signed-off-by: Jin Hai <haijin.chn@gmail.com>

api/db/services/document_service.py

@@ -34,7 +34,8 @@ from api.db.db_models import DB, Document, Knowledgebase, Task, Tenant, UserTena
 from api.db.db_utils import bulk_insert_into_db
 from api.db.services.common_service import CommonService
 from api.db.services.knowledgebase_service import KnowledgebaseService
-from api.utils import current_timestamp, get_format_time, get_uuid
+from api.utils import get_uuid
+from common.time_utils import current_timestamp, get_format_time
 from rag.nlp import rag_tokenizer, search
 from rag.settings import get_svr_queue_name, SVR_CONSUMER_GROUP_NAME
 from rag.utils.redis_conn import REDIS_CONN