Add is_translation to mod with backfill

Now, the update command will scrape all non-translation mods and translation mods separately so the is_translation value can be set correctly in the future.

src/commands/mod.rs

@@ -1,3 +1,4 @@
+pub mod backfills;
 pub mod download_tiles;
 pub mod dump_cell_data;
 pub mod dump_cell_edit_counts;