Motivation for this change

Souffle has had two major releases since 1.0.0. We push to the newest release.

We also remove two fixed that were previously needed but not seem to cause issues anymore:

• enable parallel building - parallel building doesn't seem to cause issues anymore (testes with -j 4)
• enable hardening through Fortify, since the bug seems to be fixed, See Crash with -D_FORTIFY_SOURCE=2 on Linux souffle-lang/souffle#176

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option build-use-sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.