yarn2nix: remove deprecated yarn2nix fetch script

pkgs/development/tools/yarn2nix-moretea/fetch-source.nix

@@ -1,10 +0,0 @@
-{ pkgs ? (import ../../../../. {})
-, fetchFromGitHub ? pkgs.fetchFromGitHub
-}:
-
-fetchFromGitHub {
-  owner  = "moretea";
-  repo   = "yarn2nix";
-  rev    = "9e7279edde2a4e0f5ec04c53f5cd64440a27a1ae";
-  sha256 = "0zz2lrwn3y3rb8gzaiwxgz02dvy3s552zc70zvfqc0zh5dhydgn7";
-}

pkgs/development/tools/yarn2nix-moretea/generate.sh

@@ -1,40 +0,0 @@
-#!/usr/bin/env bash
-
-###
-### This script runs 'nix-build' with ./fetch-source.nix and copies a subset
-### of the resulting store path into the current working directory.
-###
-### To disable running chmod, you may set the environment
-### variable "FIX_RIGHTS" to "no".
-###
-
-set -euo pipefail
-
-# 'nix-build' command
-NIX_BUILD_BIN="${NIX_BUILD_BIN:-"/usr/bin/env nix-build"}"
-
-# where to place the yarn2nix source
-TARGET_DIR="${TARGET_DIR:-"./yarn2nix"}"
-
-# whether to run 'chmod -R u=rwX,g=rX,o-rwx' on copied files in $TARGET_DIR
-FIX_RIGHTS="${FIX_RIGHTS:-"yes"}"
-
-fetch_git_source() {
-  [[ -f ./fetch-source.nix ]] && ret="$($NIX_BUILD_BIN --no-out-link ./fetch-source.nix)" && ec="$?" || ec="$?"
-  if [[ "$ec" == "0" ]]; then
-    echo "$ret"
-  else
-    printf "error: failed at 'fetch_git_source()' with '%s'" "$ret"
-  fi
-}
-
-result="$(fetch_git_source)"
-if [[ "$result" == "/nix/store"* ]]; then
-  mkdir -p "$TARGET_DIR"
-  cp -Rv \
-    "${result}/"{bin,internal,lib,nix,default.nix,package.json,yarn.nix,yarn.lock,LICENSE.txt} \
-    "$TARGET_DIR"
-  [[ "$FIX_RIGHTS" = "yes" ]] \
-    && chmod -v "u=rwX,g=rX,o-rwx" -R \
-    "$TARGET_DIR/"{bin,internal,lib,nix,default.nix,package.json,yarn.nix,yarn.lock,LICENSE.txt}
-fi