Motivation for this change

The udev rules shipped with platformio are not part of the package output. This is a follow up to #91679 (I'll close the PR when this gets merged)

Things done

Put the udev rules into $out/lib/udev/rules.d/99-platformio-udev.rules. This also adds a patch to change the default warning when the rules are not found to a more NixOS specific message.

Some things feel weird for me:
1.) Is calling fetchFromGitHub in multiple places with the same arguments considered good style? I could not think of a better way to do this.
2.) Is patching a appropriate way to inform about the usage of the udev rules?

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• 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 nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.