Acts-344 fatras adaptions

This merge request contains needed adaptions to use acts-fatras. Fixes ACTS-344.

1. A few slightly different/or often even the same implementations of energy loss and multiple scattering existed in acts-core and acts-fatras. Also documentation was missing. After this merge request there will only exist one implementation of energy loss due to ionization (using the most probable value for simulation and the average value for reconstruction), radiation and multiple scattering. The energyloss due to ionization and the multiple scattering have been validated for Fatras against Geant4 for muons. The energyloss for electrons needs still to be implemented and validated.
2. This merge request enables building of layers which do not contain any sensitive surfaces but carry material.