Roles '{flamenco,attract}-user' are now linked to 'subscriber'

All users who get 'subscriber' role automatically get 'flamenco-user' and
'attract-user', and when 'subscriber' is revoked, so are
'{flamenco,attract}-user'.

setup.cfg

@@ -0,0 +1,5 @@
+[tool:pytest]
+addopts = -v --cov cloud --cov-report term-missing --ignore node_modules --ignore docker
+
+[pep8]
+max-line-length = 100