Added installation prerequisites for rustup, uv, just, and MSVC

[Hamza1610]

Description

This PR adds a Prerequisites section to the README.md listing the core tools required to build bdkpython locally: rustup, uv, just, and Visual Studio C++ Build Tools for Windows (MSVC target).

Fixes #47

Notes to the reviewers

While setting up the repo on Windows, I noticed the README didn't mention setup dependencies like rustup or MSVC build tools needed by cargo build. Adding this helps new contributors quickly verify their local environment before running the build scripts.

Changelog notice

• Added installation prerequisites section to README.md

Checklists

All Submissions:

• I've signed all my commits
• I followed the contribution guidelines

New Features:

• I've added docs for the new feature

[thunderbiscuit]

Thanks for taking a look and running our docs through the Windows lens!

I have two small ideas, but let me know if you think they don't make sense (particularly the 2nd one).

[thunderbiscuit]

This line I'm less clear on: I thought cargo had those for you by default.

[thunderbiscuit]

After looking into this, I propose this line instead:

- **`just`**: Command runner used for repo tasks. Install via `cargo install just` or your system package manager.

_Windows Users_
- **Windows**: Rust's `x86_64-pc-windows-msvc` target needs the MSVC toolchain and Windows SDK. `rustup-init` offers to install these for you; otherwise install Visual Studio Build Tools with the *Desktop development with C++* workload. The build scripts are bash, so run them from Git Bash.

[thunderbiscuit]

The rest of the readme doesn't require just, so I suggest you add it as (optional):

- **`just` (optional)**: Command runner used for repo tasks. Install via `cargo install just` or your system package manager.