Add commands to generate translation file and check they're updated

Author: silvanocerza

Diff for: package.json

@@ -43,6 +43,8 @@
     "test": "lerna run test",
     "download:plugins": "theia download:plugins",
     "update:version": "node ./scripts/update-version.js",
+    "i18n:generate": "theia extract -p '+(arduino-ide-extension|browser-app|electron|electron-app|plugins)/**/*.ts' -o ./i18n/en.json",
+    "i18n:check": "yarn i18n:generate && git add -N ./i18n && git diff --exit-code ./i18n",
     "i18n:push": "node ./scripts/i18n/transifex-push.js ./i18n/en.json",
     "i18n:pull": "node ./scripts/i18n/transifex-pull.js ./i18n/"
   },