Consider Switching Tar Libs

The classic tar lib cabal uses is only maintained on a maintenance basis. There are outstanding issues with processing unicode and long filenames (especially but not only) which can bite cabal users. The long filename issue has bitten me in the hackage builder a number of times.

There's a fork here https://hackage.haskell.org/package/tar-bytestring from @hasufell which fixes some of this stuff, though it introduces an hpath dep for some reasons i'm not clear on.

Maybe we could move to the fork and either accept the hpath dep or get the fork to not use it. Or maybe we could get an active maintainer for tar to fix the most irritating outstanding issues (borrowing from the fork).

Or, we could potentially move to libarchive, but that entails an FFI binding and perhaps that is to be avoided.