supprime la branche nalc de plusieurs sous-modules

serverguide, shutdown, signs_lib (avec changement d'url), snow,
spears, sponge, stained_glass (avec changement d'url)

.gitmodules

@@ -271,31 +271,24 @@
 [submodule "serverguide"]
 	path = serverguide
 	url = https://sys4.fr/gitea/nalc/serverguide.git
-	branch = nalc
 [submodule "shutdown"]
 	path = shutdown
 	url = https://sys4.fr/gitea/nalc/shutdown.git
-	branch = nalc
 [submodule "signs_lib"]
 	path = signs_lib
-	url = https://sys4.fr/gitea/nalc/signs_lib.git
-	branch = nalc
+	url = https://sys4.fr/gitea/mtcontrib/signs_lib.git
 [submodule "snow"]
 	path = snow
 	url = https://sys4.fr/gitea/nalc/minetest-mod-snow.git
-	branch = nalc
 [submodule "spears"]
 	path = spears
 	url = https://sys4.fr/gitea/nalc/spears.git
-	branch = nalc
 [submodule "sponge"]
 	path = sponge
 	url = https://sys4.fr/gitea/nalc/sponge.git
-	branch = nalc
 [submodule "stained_glass"]
 	path = stained_glass
-	url = https://sys4.fr/gitea/nalc/stained_glass.git
-	branch = nalc
+	url = https://sys4.fr/gitea/minetest-mods/stained_glass.git
 [submodule "technic"]
 	path = technic
 	url = https://sys4.fr/gitea/nalc/technic.git