formula: add alibaba/async_simple

[MeteorsLiu]

Summary

• Add an idiomatic LLAR Formula for the pinned Conan Center async_simple recipe.
• Cover the complete upstream tag set with the optional-v comparator and fromVer 1.0.
• Preserve header-only, static, and shared package outputs with relocatable pkg-config metadata and an independent consumer test.

Validation

• LLAR main 9c062aa5c4b1724bfd30cb72f7e0bda136f9c078.
• Exact tags 1.0, 1.1, 1.2, v1.3, and 1.4 default consumer on darwin-arm64.
• v1.3 static, shared, and fPIC=OFF matrices on darwin-arm64.
• Oldest 1.0 compiled package and cache-hit consumer test.

Closes #281

[fennoai]

Reviewed the complete async_simple formula addition, including version normalization, option filtering, header/library packaging, relocatable pkg-config metadata, and the consumer path. I found no actionable correctness or regression issues in the changed code.

Verification completed against the fixed PR commits:

• llar test for tags 1.0, 1.1, 1.2, v1.3, and 1.4 on Linux amd64.
• Compiled header_only=OFF variants for static/fPIC and shared/non-fPIC option combinations.
• git diff --check passed.