Enable npm workspaces by default

### Expected Behaviour
Enable [NPM Workspaces](https://docs.npmjs.com/cli/v7/using-npm/workspaces) in the _ui.frontend_ module by default and allow selecting more than one frontend option (e.g.: general AND angular). This way a monorepo structure is created and easily extendable to foster reusability.

### Actual Behaviour
Only one npm package is created.

Start by inspecting the ui.frontend module and the archetype inputs that select frontend options. Verify how the current project creates its single npm package, then define done as enabling npm workspaces by default and allowing multiple options such as general and angular to produce an extendable monorepo structure.

Written by the indexing model from the issue text.