A panic within `createCsbiDevice` does not result in a crash

- Removed Goroutine in `createCsbiDevice` and calls of `panic()` have been
  changed to `return err`
- `createCsbiDevice` is now called as Goroutine from within the
  `handleCsbiEnrolment` method.
- Error handling is done by using a `ErrorGroup`

These changes prevent that panics are thrown from a Goroutine that was
originally called from `createCsbiDevice`. Now normal errors are thrown
and catched with the help of a `ErrorGroup`.

Fixes: #171