WASI 0.2 (wasip2) launched 2024-01-25 with ABI changes that make it incompatible with WASI 0.1 (wasip1).

I propose we;

• Add //cpu:wasip2
• Rename //cpu:wasi to //cpu:wasip1, leaving behind an alias for backward compatibility.

This mirrors what Rust (tier 3, tier 2) and LLVM have done.

This is an existing issue requesting constraints for ABI, #38. It may make sense to keep //cpu:wasi as it is and instead have a separate ABI constraint.

Another consideration is CPU feature sets, since wasip2 is more than just an ABI change. In some ways it is similar to micro-architecture levels (e.g. x86-64-v4, ARMv9.0-A), which bares similarity to what #13 is requesting.