Move static assets out of the projects

### BIG CHANGE

This moves the static assets, that currently live in e.g. `common/app/assets` -> `static/src`

Impetus was pulling in the fonts which we couldn't do neatly, as they we're stored in the common project and being bundled up in every artifact = big artifact sizes

Having the assets in the common project was a hangover from when Play used to handle our asset compilation. There's no reason for it to live there now

Dir structure is basically the same, except project's JS now lives in `static/src/javavascripts/projects/<project>`

Sorry