Update to RGBDS 1.0 syntax and features

The tutorial has been written gradually over years by different authors, and in that time, RGBDS syntax has been through pretty many changes. Now that it's reached v1.0.0 the syntax is stable enough that I think it would be worth going through the code in the tutorial and ensuring that it's valid and idiomatic for the latest RGBDS.

(For example, [the Galactic Armada Makefile](https://github.com/gbdev/gb-asm-tutorial/blob/master/galactic-armada/Makefile) has `$(GFX) -c "#FFFFFF,#cfcfcf,#686868,#000000;"`, which would now idiomatically be `$(GFX) -c dmg`, and which could be enabling `-Weverything` warning diagnostics. The code itself might all still be simple enough -- no fancy macros or metaprogramming -- that nothing would need change, but the CLI usage at least could be improved.)

See also #125

Examinez le code du tutoriel et le Makefile de Galactic Armada au regard de la syntaxe et des conventions CLI de RGBDS 1.0, en commençant par l’exemple de Makefile décrit dans l’issue. Utilisez l’issue #125 comme contexte associé, puis vérifiez que le tutoriel reste valide et idiomatique et que ses commandes ne reposent plus sur une utilisation obsolète.

Rédigé par le modèle d'indexation à partir du texte de l'issue.