Automate installation with Composer
So since nobody provided acceptable answer, based on the above comments I tried the following bash-script and it worked flawlessly: 

sudo -u $USER /usr/local/bin/composer --quiet create-project drupal-composer/drupal-project:8.x-dev $HOME/public_html --stability dev --no-interaction
cd $HOME/public_html/web
drush si -y \
  --db-url=mysql://$MYSQL_USER:$PASS@localhost/$DB \
  --site-name=$DOM \
  --site-mail=$EMAIL \
  --account-mail=$EMAIL \
  --account-name=$USER \
  --account-pass=$PASS &gt;&gt; /dev/null 2&gt;&amp;1