[PWGLF] Add OO cascade-enriched ini file

Leverages existing extra-strangeness code and just switches the cfg file to the common OO one.

Author: ddobrigk

MC/config/PWGLF/ini/GeneratorLF_Strangeness_OO5360_injection.ini

@@ -0,0 +1,6 @@
+[GeneratorExternal]
+fileName=${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGLF/pythia8/generator_pythia8_extraStrangeness.C
+funcName=generator_extraStrangeness()
+
+[GeneratorPythia8]
+config=${O2DPG_MC_CONFIG_ROOT}/MC/config/common/pythia8/generator/pythia8_OO_536.cfg