systems_design: implement a low fidelity method

TODO

Summary

As discussed in the UNICADO workshop https://git.rwth-aachen.de/unicado/unicado-package/-/issues/46, the current systems_design method is an extensive method designing different ATA chapter in detail. To reduce the complexity, it was discussed whether a new method estimating the overall system as one "virtual system" could be implemented as used as default setting.

Subtasks

to be defined

Acceptance Criteria

to be defined