Adapt HF example to recent O2 updates

Author: preghenella

MC/config/PWGHF/ini/GeneratorHF.ini

@@ -1,7 +1,14 @@
+### The setup uses an external event generator
+### This part sets the path of the file and the function call to retrieve it
+
+[GeneratorExternal]
+fileName = ${O2DPG_ROOT}/MC/config/PWGHF/external/generator/GeneratorHF.C
+funcName = GeneratorHF()
+
 ### The external generator derives from GeneratorPythia8.
 ### This part configures the bits of the interface: configuration and user hooks
 
-[Pythia8]
+[GeneratorPythia8]
 config = ${O2DPG_ROOT}/MC/config/common/pythia8/generator/pythia8.cfg
 hooksFileName = ${O2DPG_ROOT}/MC/config/PWGHF/pythia8/hooks/pythia8_userhooks_ccbar.C
 hooksFuncName = pythia8_userhooks_ccbar(1.5)

MC/run/PWGHF/run_embedding.sh

@@ -32,9 +32,7 @@ ${O2DPG_ROOT}/MC/config/common/pythia8/utils/mkpy8cfg.py \
 # embed signal into background
 
 o2-sim -j ${NWORKERS} -n ${SIGEVENTS} -g extgen -m ${MODULES} -o sgn \
-       --extGenFile ${O2DPG_ROOT}/MC/config/PWGHF/external/generator/GeneratorHF.C \
-       --extGenFunc "GeneratorHF()" \
        --configFile ${O2DPG_ROOT}/MC/config/PWGHF/ini/GeneratorHF.ini \
-       --configKeyValues "Pythia8.config=pythia8.cfg" \
+       --configKeyValues "GeneratorPythia8.config=pythia8.cfg" \
        --embedIntoFile bkg_Kine.root \
        > logsgn 2>&1