Do not rely on request ids for navigation in the internal data structure

[skliche]

Currently the references in the internal data structure are build upon the external ids of the rm logs. While this logically makes sense (the external rm data is the source of the internal data structure) it creates the risk that the internal data structure contains loops or circular references at various points.

In order to prevent that (and by that remove the necessity to handle loop situations several times) we should generate reference ids internally (but never show them in the ui).