Fix boundary misses by re-targetting
Closes #681 (closed)
The purpose and fix of this MR is described in detail in #681 (closed). It introduces:
- a re-targetting of boundary surfaces in case the portal navigation stream is lost
- the possibility to switch the stepping logger to sterile, in order to allow single track debugging
This is the result of one million tracks navigated through the generic detector at 2 T constant field: