try to read SECRET_KEY from environment (while allowing other methods for setting it later)
remove misleading default of STATIC_ROOT

it is the destination directory of manage.py collectstatic action, NOT our main app's static dir
offer test account
remove the screenshots view, it is prone to be outdated and boring work to keep it uptodate

it is replaced by a hint to use a test account, so you can see it all "live" - without needing to register first.