Update README: New Features, Deployment Guides Enhancements

[Mefisto04]

Description:

• Added new MemFree feature descriptions and capabilities.
• Updated deployment guides for Zeabur, Vercel, and Fly.io.
• Enhanced sections on MemFree's value propositions and tech stack.

This PR enhances the README file with clearer instructions, new features, and updated deployment steps.

[Mefisto04]

All this changes mention in #13, @ahaapple please review this

[ahaapple]

Thank you very much for your contribution

[ahaapple]

@Mefisto04 Hi，Thank you for your contribution to MemFree.

In return, if you are interested, I can give you a 20% discount code for MemFree. You can send me a private message via discord, Twitter or email.

Looking forward to your more contributions to MemFree. Let us work together to make MemFree better and better.