Widget - Duplicate nodeNames and changing MACs are now supported

This PR adds

- [x] Support to identify an inserted node when its MAC changes
- [x] Support to add multiple nodes with the same name (_needed for Lübeck_)
- [x] Fixed Unittests and PHPCS for the additions
- [ ] MAC hashing uses **weak** `sha1()` algorithm, we need to use `hash('sha256', $mac)` or similar instead.
- [ ] MACs are hashed without any **salt**. An implementation for a `parameter.mac_salt` would help.