p7zip{,-rar}: swap build with symlinks to _7zz{,-rar}

[06kellyjac]

Follow up to #433137

• p7zip{,-rar}: swap build with symlinks to _7zz{,-rar}
• p7zip{,-rar}: add release note
• _7zz: add 7z unpack hook to setup-hook
• pianoteq: switch to _7zz and auto unpack
• sweethome3d: switch to _7zz
• balatro: switch to _7zz
• bink-player: switch to _7zz and auto unpack
• binwalk: switch to _7zz
• briar-desktop: switch to _7zz
• dsq: switch to _7zz
• exactaudiocopy: switch to _7zz
• far2l: switch to _7zz
• kinect-audio-setup: switch to _7zz
• lightburn: switch to _7zz and auto unpack
• losslesscut-bin: switch to _7zz
• rounded-mgenplus: switch to _7zz
• sabnzbd: switch to _7zz
• shanggu-fonts: switch to _7zz
• snap7: switch to fetchurl and _7zz with unpack in build
• svp: switch to _7zz
• vk-cli: switch to _7zz and auto unpack
• wargus: switch to _7zz
• webex: switch to _7zz and auto unpack
• win-spice: switch to _7zz
• xarchiver: remove p7zip
• python314Packages.extractcode-7z: switch to _7zz
• python314Packages.patool: switch to _7zz
• linuxPackages.ply: switch to _7zz
• linuxPackages.prl-tools: switch to _7zz

This is a rebase of some older work around the time of #433137 minus a few changes for dropped packages

I'll leave this as draft to get thoughts and do a full build of changed packages.
I might also have to shift this to staging depending on the amount of affected packages.

Things done

• Built on platform:
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• Tested, as applicable:
  • NixOS tests in nixos/tests.
  • Package tests at passthru.tests.
  • Tests in lib/tests or pkgs/test for functions and "core" functionality.
• Ran nixpkgs-review on this PR. See nixpkgs-review usage.
• Tested basic functionality of all binary files, usually in ./result/bin/.
• Nixpkgs Release Notes
  • Package update: when the change is major or breaking.
• NixOS Release Notes
  • Module addition: when adding a new NixOS module.
  • Module update: when the change is significant.
• Fits CONTRIBUTING.md, pkgs/README.md, maintainers/README.md and other READMEs.