Add and fix Japanese translation (#2904)

mods/bucket/locale/bucket.ja.tr

@@ -0,0 +1,5 @@
+# textdomain: bucket
+Empty Bucket=空のバケツ
+Water Bucket=水入りバケツ
+River Water Bucket=川の水入りバケツ
+Lava Bucket=溶岩入りバケツ