Intllib support

[ghost]

Added support for Internationalization Library (intllib) Meaning :

• added call to intllib.Getter init.lua,
• rewrote all text string as S("string")
• added locale folder with template.txt

I also added french translation

I might soon do the same to handle_schematic mod as this is the one setting the first infotext meta for the plot marker I might also open an other branch to fix ugly text overlaying on small screens (because French translation having some longer strings, this is even worse)

[Sokomine]

Manually merged.