Added Basque translation (#3195)

Co-authored-by: bilbao_iban <bilbao_iban@eitb.eus>

mods/carts/locale/carts.eu.tr

@@ -0,0 +1,6 @@
+# textdomain: carts
+Cart=Bagoneta
+(Sneak+Click to pick up)=(Makurtzea + Klik jasotzeko)
+Rail=Erraila
+Powered Rail=Errail energizatua
+Brake Rail=Balaztatze-erraila