Add export and import translation scripts

Closes: #430

devtools/import-translation.sh

@@ -0,0 +1,8 @@
+#!/bin/zsh
+
+if [ -z "$*" ]; then
+  echo "Usage: ./devtools/import-translation.sh <locale_code_in_snake_case>"
+  return
+fi
+
+find "translations" -name "${1}.xliff" | grep -v "en-US.xliff" | xargs -I % xcodebuild -importLocalizations -project damus.xcodeproj -localizationPath %