[WIP] Add features flag for cargo stylus check/deploy

[cygaar]

Description

It would be convenient if developers could specify which features they want to include when checking/deploying their stylus contracts. In my case, I'm working on a set of common contracts (similar to Openzeppelin, Solmate, Solady etc) in Rust where I gate different libraries (ERC20, ERC721, ERC1155, etc) through crate features.

The core issue is that I have multiple example contracts each with an entrypoint. By adding a features flag to cargo stylus, I'll be able to check different features easily without having to manually build and specify a wasm-path when running the check command.

Checklist

• I have documented these changes where necessary.
• I have read the DCO and ensured that these changes comply.
• I assign this work under its open source licensing.