Move asset files into specific folder in bucket

The following discussion from !34 (merged) should be addressed:

• @allison.browne started a discussion: (+1 comment)

  Non-Blocking: Would it may make sense to keep the the application assets (css/js) at a specific prefix perhaps app? That would allow for aws s3 sync dist "s3://$S3_BUCKET_NAME/app" --delete" and would allow for adding other long lived resources outside of app without adding them here.