Add lief to shrinkwrap and remove patchelf

[fzakaria]

Add the necessary scaffolding to add lief as a dependency.

• swap out some of the patchelf functionality for native cpython integration via lief
• remove coreutils since now we don't rely on bin/cp for copy (that was egregious)
• improve the poetry2nix setup after scouring GitHub for examples (Thank you @lovesegfault)
• add flake checks to make the CI process simpler and more robust
• remove patchelf

[fzakaria]

CC @trws

[fzakaria]

Don't inspect you to review -- it's a big PR. I'll keep it here for a bit before merging.

[trws]

LGTM, lot of changes but they're all coherent and look good.