Refactor Package structure

This commit cleans up the package structure, to make two new top-level
packages `internal` (for internal-use packages) and `pkg` (for general
shared utility code).

internal/core/runtime/use_wisski.sh

@@ -0,0 +1,22 @@
+#!/bin/bash
+set -e
+
+# read user
+VERSION=$1
+if [ -z "$VERSION" ]; then
+    echo "Usage: use_wisski.sh VERSION"
+    exit 1
+fi
+
+# update the main modules
+cd /var/www/data/project
+chmod u+rw web/sites/default/
+composer require "drupal/wisski:$VERSION"
+
+# update the wisski dependencies
+pushd /var/www/data/project/web/modules/contrib/wisski
+composer update
+popd
+
+# update the db
+drush -y updatedb