Move scraper to subfolder and initialize new Vue.js project

[dan-niles]

As part of #165, we need to move the scraper related files into a subfolder called scraper and initialize a new Vue.js project in a folder called zimui.

This will be as the same approach followed in the Kolibri UI revamp.

[dan-niles]

With #207, we are switching to "on-the-fly" items addition to the ZIM by using Creator instead of make_zim_file, this allows for more customisability when creating the ZIM, since now we have to include the static website created using Vue.js inside the ZIM file.