Support Direct Import in the open source lib

[liu1700]

🚀 The feature

Bypass the memory deduction phase and directly store pre-defined memories for efficient retrieval Exactly same as https://docs.mem0.ai/features/direct-import But in the open source lib

Motivation, pitch

I'm working on an ai agent project using the open source lib with self-hosted server and database, and I'd like direct import also available in the Open sourced lib. I can submit a PR for it.