Add a 'More' button to add more elements to the page

[sanspace]

A button with an onclick event to clone the row element should do. We're already doing it in script.js:5 https://github.com/sanspace/bargen/commit/b0d0f52afb5e511556fa3b4d24f78a28fa8cec8b#diff-9a9569e9d73f33740eada95275da7f30/script.js#5