Merge changes from topics "build-aconfig", "build-libprotobuf-for-host-only" into main

* changes:
  Allowlist aconfig
  Implement bp2build converter for rust_protobuf_host
  Implement bp2build converter for rust_binary
  Convert libprotobuf to Bazel
  Allowlist all aconfig deps modulo libprotobuf and libaconfig_protos
  Implement bp2build converter for rust_proc_macro
  Allowlist rust_library dependencies of aconfig
  Implement bp2build converter for rust_library