⚗️ Try to eliminate the need for the start parameter in DD routines

[burgholzer]

What's the problem this feature will solve?

Many of the DD routines throughout the package include a start parameter that is supposed to indicate the lowest index in the DD. This was mainly introduced for the Hybrid Schrödinger-Feynman (HSF) simulator and isn't used anywhere else.
As such, it is kind of a nuisance and leads to a lot of special handling throughout some of the functions.

Describe the solution you'd like

It should be possible to work around this requirement by refactoring parts of the HSF simulator.

Related down-stream issue:

• ⚗️ Try to get rid of the start parameter in DD routines mqt-core#345