[Feature Request] Add mmap module

[tairov]

Review Mojo's priorities

• [X] I have read the roadmap and priorities and I believe this request falls within the priorities.

What is your request?

Implement mmap module natively in Mojo link: https://man7.org/linux/man-pages/man2/mmap.2.html

What is your motivation for this change?

When implementing multiple solutions on Mojo, we reached a stage where huge files needed to be loaded into memory (for example, open source llm models).

For these purposes, it would be really great to have the mmap module implemented natively in Mojo.

Any other details?

No response