Make the toolkit-showcase package part of the main workspace package

It's confusing that there are two lock files in this repo and two overlapping workspaces. Ideally everything should be in sync.

toolkit-showcase/package.json

@@ -4,10 +4,6 @@
   "main": "src/toolkit-showcase.js",
   "license": "LGPL-2.1-or-later",
   "private": true,
-  "workspaces": [
-    "../packages/*",
-    "."
-  ],
   "devDependencies": {
     "@babel/core": "^7.10.3",
     "@babel/plugin-syntax-dynamic-import": "^7.8.3",
@@ -74,8 +70,6 @@
     "watch-local": "yarn run watch",
     "watch-full": "rollup -c --watch --environment FORCE_FULL",
     "watch-bs": "rollup -c --watch --environment APP_ENV:bs",
-    "test": "rollup -c --environment APP_ENV:test && karma start --singleRun",
-    "test-full": "rollup -c --environment FORCE_FULL,APP_ENV:test && karma start --singleRun",
     "lint": "eslint ."
   }
 }