Added Brazilian Portuguese translation (#2834)

Added the Brazilian Portuguese translation to all mods in the Minetest Game.

mods/xpanes/locale/xpanes.pt_BR.tr

@@ -0,0 +1,6 @@
+# textdomain: xpanes
+Glass Pane=Painel de Vidro
+Obsidian Glass Pane=Painel de Vidro de Obsidiana
+Steel Bars=Barras de Aço
+Steel Bar Door=Porta de Barras de Aço
+Steel Bar Trapdoor=Alçapão de Barras de Aço