Use Solana 2.1 crate dependencies on Rust renderer

[febo]

Problem

From version 2.1, solana-program has been split up in individual crates. While it is still possible to depend directly on solana-program, the Rust client could reduce its dependency graph by only importing the crates that is needs (e.g., solana-pubkey and solana-instruction).

Proposed Solution

Update the renderer-rust package to use individual dependencies. This unfortunately will make the generated clients dependent on the new 2.1 version of the crates, although the previous version of the package could still be used to generate clients with solana-program dependency.