[PWGJE] templatization of process functions to accomodate D0 and Lc jets to charm hadronisation analysis

[christianreckziegel]

Originally, this task consisted of three independent process functions to store D⁰-jet information:

• one for DATA
• two for MC (one for efficiency estimation and one for detector–particle level matching)

This PR refactors and generalizes the implementation to support additional heavy-flavour hadrons (in particular Lc) while preserving the original analysis logic.

Minor changes

• Renamed histogram identifiers from _d0_ to the more generic _hf_
• Renamed process functions accordingly to reflect heavy-flavour–agnostic behavior

Major changes

• To enable the same analysis to run for both D⁰ and Lc hadrons, the following process functions were refactored into templated implementations, which are invoked from dedicated process functions for each hadron species:
  • formerly processDataChargedSubstructure()
  • formerly processMcChargedMatched()
• The MC process function responsible for storing jet–hadron matching information has been extended:
  • it now stores all particle-level entries, including cases with no detector-level match
  • this allows a more complete characterization of matching and unmatched contributions