Move LLNDK related logic to llndk_library

Currently VNDK contains some logic for LLNDK libraries as they are
treated in a similar way with VNDK. However, those logics should stay from
VNDK deprecation. To keep the logic, this change moves LLNDK related
logic into llndk_library.

Bug: 330100430
Test: Soong tests passed
Test: llndk.libraries.txt did not change from CF build
Change-Id: I1d02a3c2a398f1b1060b4f2bdd23af32310503bb