Implement export of item icons and locale

Add mod and command for exporting the Factorio locale including mods,
and item icons assemled into a sprite sheet including mods.

package.json

@@ -45,6 +45,7 @@
     "follow-redirects": "^1.5.0",
     "fs-extra": "^8.1.0",
     "ini": "^1.3.5",
+    "jimp": "^0.12.1",
     "jsonwebtoken": "^8.2.1",
     "jszip": "^3.2.2",
     "lib": "file:./lib",