[WIP] replaced reflections from bundles action with configuration in admin

This PR changes the way the javascript from the bundles is included. From now on there have to be a getJsBundleName function returning the correct folder for loading the main javascript file (e.g. `sulucontact` for /bundles/sulucontact/js/main.js, the part around sulucontact is generated)

__Tasks:__

- [ ] test coverage
- [ ] gather feedback for my changes
- [ ] submit changes to the documentation


__Informations:__

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| Tests pass?   | yes
| Fixed tickets | none
| Doc           | none