Convert from rmcp to rust-mcp-sdk

[subpop]

Each tool now lives in a separate module. This approach scales better than the rmcp approach of putting all tools on one struct.

[brianredbeard]

I get breaking things down into separate modules, but what as the idea around removing src/lib.rs completely? Are there no longer any shared functions or interfaces across the tools?

[subpop]

Yea I questioned that myself. The modules are declared in main.rs directly, meaning there is no library crate. I guess that's okay considering this is mean to be a binary distribution, but having a library crate could make internal reuse easier too. I didn't come to a final decision. I'll add another commit that puts in a library crate and we can see what it looks like.