Use concrete event data types in Fatras

Adds ActsFatras::Barcode from the framework and streamlines the existing ActsFatras::Particle type. Most places that were previously templated on the detector and particle type now use Acts::MaterialProperties and ActsFatras::Particle directly. Adds some missing tests as well.

The ActsFatras::Barcode used a slightly different encoding from the one currently used in the framework. The modifications allow better encoding of secondaries. A detailed explanation is given in the Barcode.hpp file.

Contains some drive-by fixes and cleanups in preparation of #698 (closed).

Fixes half of #696 (closed).