Giant refactorizing for localization

It is me again, I rewrote almost every layouts in order to have localization.

I tried not to broke anything, but it is pretty hard to confirm that even if this should be fine.

I removed almost every hard coded strings which have no parameters. Application is thus almost fully translatable to other languages.

If this PR is merged, something about **stop hard-coding texts** in the guide lines would be great ;-)
Yes, this is optional but it avoids the need to escape single quote en stuff like that, so I tend to prefer it. Both formats can still live together.