Add basics/transfer-sol/steel

[robertohuertasm]

Adds a transfer sol example using the Steel framework containing both Bankrun tests and Rust tests.

Uses Steel 2.1 and latest helper methods send and collect.

[heyAyushh]

Thanks for your contribution! Before we can merge this PR, please:

1. Merge main branch into your PR to get the latest updates
2. Run pnpm fix at the project root to ensure code style consistency
3. Remove the steel program entry from the root Cargo.toml if present
4. Run cargo fmt and cargo clippy to ensure Rust code quality
5. Push your changes

Let me know once you've completed these steps and I'll review again. Thanks!

[robertohuertasm]

Hi @heyAyushh! Done! I assumed for 3 you meant from here? If that's the case, it's not present.