Consider moving llvm-addr2line/llvm-symbolizer into its own package so that it can be used by Boost.Stacktrace

[SwooshyCueb]

Presently, we use the addr2line backend for Boost.Stacktrace, but it uses the version of addr2line provided by the system.
Our clang package contains llvm-addr2line, which is sometimes more effective than the system-provided implementation.
(llvm-addr2line is really just a symlink to llvm-symbolizer, which checks argv[0] to switch on compatibility with GNU addr2line if needed.)
Should we decide against switching to the backtrace backend for Boost.Stacktrace (see irods/irods#6146), we should consider creating a new package à la clang-runtime that contains llvm-addr2line and llvm-symbolizer so that it can be used by Boost.Stacktrace.