nodePackages: cleanup/fix overrides
nodePackages: cleanup/fix overrides

* Standardize on `override` vs `overrideAttrs'.
* Use `oldAttrs` as standard argument to `override` when it's needed.
* Fix overrides of `meta` so that original attributes are preserved.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs