Moved algorithms to Gaudi::Functional framework.
All algorithms in FTDigitisation have been moved to Gaudi::Functional (many thanks to @pluca). Corresponds to JIRA task LHCBSCIFI-83. In addition the NextNext spill has been removed from the simulation (LHCBSCIFI-86). The Rnd::Numbers have been made mutable (is there a better solution available?). We did not touch the Linkers for the moment.