Add wrapper script for pybabel

* because we moved away from setuptools which had wrappers

babel.sh

+#!/bin/bash
+
+if [[ $# -lt 1 ]]; then
+    echo >&2 "error: expected at least one argument"
+fi
+
+case "${1}" in
+    init)
+        pybabel init \
+            --input-file "invenio_utilities_tuw/translations/messages.pot" \
+            --output-dir "invenio_utilities_tuw/translations/"
+        ;;
+    compile)
+        pybabel compile \
+            --directory "invenio_utilities_tuw/translations/"
+        ;;
+    extract)
+        pybabel extract \
+            --copyright-holder "TU Wien" \
+            --msgid-bugs-address "tudata@tuwien.ac.at" \
+            --mapping-file "babel.ini" \
+            --output-file "invenio_utilities_tuw/translations/messages.pot" \
+            --add-comments "NOTE"
+        ;;
+    update)
+        pybabel update \
+            --input-file "invenio_utilities_tuw/translations/messages.pot" \
+            --output-dir "invenio_utilities_tuw/translations/"
+        ;;
+    *)
+        echo >&2 "unknown command: ${1}"
+        exit 1
+        ;;
+esac