Default STATIC_ROOT and database paths

[mrnerdhair]

Without STATIC_ROOT, the project won't start at all, so there should be a default. Since the default DB path was originally under BASE_DIR, it makes sense that the static path would be too.

Furthermore, the DB itself should be stored in a folder dedicated to Scirius data; otherwise it's not clear which files should be persistent.(Also, you can't mount a Docker volume onto a single file!)