Add the Vue.js frontend integration to the Django BoxUI project

This branch adds Vue.js integration:

• Add Vue, vuex, eslint, i18n
• Add Django-webpack-tracker to include latest built bundle in the webapp served by Django
• Add vue-cli/webpack-tracker to the local.yml Docker-compose file

Fixes:

• Use pip install -e .[dev] instead of pip install -r requirements/requirements.txt, which was a missing bug from a previous state

Nits:

• Add site_name as a customizable variable to the webpage title