Added support for apps/ workspace

refs https://github.com/TryGhost/Toolbox/issues/594

- we want to start moving "apps" into their own folder so we can
  conceptually separate code and avoid a HUGE list in `ghost/`

package.json

@@ -7,6 +7,7 @@
   "author": "Ghost Foundation",
   "license": "MIT",
   "workspaces": [
+    "apps/*",
     "ghost/*"
   ],
   "monorepo": {