bcc: migrate to by-name

The package is left in all-packages to allow setting llvmPackages more
easily

pkgs/top-level/all-packages.nix

···
 
   bpftools = callPackage ../os-specific/linux/bpftools { };
 
-  bcc = callPackage ../os-specific/linux/bcc {
+  bcc = callPackage ../by-name/bc/bcc/package.nix {
     llvmPackages = llvmPackages_16;
   };