[doc] restore PDG and Slicing french documentation

doc/pdg/.gitignore

doc/pdg/Makefile

doc/pdg/calls.tex

doc/pdg/conclusion.tex

doc/pdg/ctrl-dpds.fig

doc/pdg/ctrl.tex

doc/pdg/data.tex

doc/pdg/ex-goto.fig

doc/pdg/goto.fig

doc/pdg/impact.tex

doc/pdg/intro.tex

doc/pdg/macros_pdg.tex

doc/pdg/main.tex

doc/pdg/mark.tex

doc/pdg/pdg-call.fig

doc/pdg/pdg.tex

doc/pdg/utilisation.tex

doc/slicing/.gitignore

doc/slicing/Makefile

doc/slicing/algo.ml