Replace `ember-crumbly`

[guidojw]

ember-crumbly is no longer maintained and it keeps us from upgrading to Node 16 (because it depends on an old version of ember-cli-babel which depends on an old version of broccoli-babel-transpiler which depends on an old version of workerpool which has a bug in Node 16).

• #651 when it is replaced, remove line

  amber-ui/package.json

  Line 116 in fca9816

  "workerpool@^2.3.0": "^2.3.4"

[DrumsnChocolate]

The source code of ember-crumbly doesn't look that complicated, right? Or am i missing something?

Edit: nvm, theres one component with some heavy logic it seems. Nevertheless, why is the babel dependency an issue? If nothing else, we can copy the implementation into our project and update our babel version, right?