[libc][bazel] Use Bazel aspects to implement libc_release_library. (#134948)
Instead of creating hundreds of implicit "filegroup" targets to keep
track of sources and textual headers required to build each libc
function or helper library, use Bazel aspects (see
https://bazel.build/versions/8.0.0/extending/aspects), which enable
transparent collection of transitive sources / textual headers while
walking the dependency DAG, and minimizes the Starlark overhead.
Co-authored-by: Jordan Rupprecht <rupprecht@google.com>