rust-eos CLI

[liamcurry]

We already have several features that need CLIs. Consolidating all our CLIs under one CLI will make things simpler for developers and allow us to add new commands later on.

Commands should be implemented to:

• Create a new rust-eos project, e.g. rust-eos new
• Generate an ABI file, e.g. rust-eos to-abi
• Generate Rust from an ABI, e.g. rust-eos from-abi
• Manage table schemas, e.g. rust-eos schema
• Run unit tests, e.g. rust-eos test