Added snippet pagination

__Tasks:__

- [x] test coverage
- [ ] gather feedback for my changes

__Informations:__

| Q             | A
| ------------- | ---
| Tests pass?   | yes
| Fixed tickets | none
| BC Breaks     | none
| Doc           | none
If I compare this to the `getSnippets`-method I would suggest to call `getSnippets` in the Controller anyway instead, and limit the results with `array_splice`. In the current way you make the same database call twice.