* flows: introduce FlowPlan markers, which indicate when a stage needs re-evaluation
Implement re_evaluate_policies
add unittests for several different scenarios
closes#78
* flows: move markers to separate files, cleanup formatting
* flows: fix self.next is not callable
* core: start migrating to flows for authorisation
* sources/oauth: start type-hinting
* core: create default user
* core: only show user delete button if an unenrollment flow exists
* flows: Correctly check initial policies on flow with context
* policies: add more verbosity to engine
* sources/oauth: migrate to flows
* sources/oauth: fix typing errors
* flows: add more tests
* sources/oauth: start implementing unittests
* sources/ldap: add option to disable user sync, move connection init to model
* sources/ldap: re-add default PropertyMappings
* providers/saml: re-add default PropertyMappings
* admin: fix missing stage count
* stages/identification: fix sources not being shown
* crypto: fix being unable to save with private key
* crypto: re-add default self-signed keypair
* policies: rewrite cache_key to prevent wrong cache
* sources/saml: migrate to flows for auth and enrollment
* stages/consent: add new stage
* admin: fix PropertyMapping widget not rendering properly
* core: provider.authorization_flow is mandatory
* flows: add support for "autosubmit" attribute on form
* flows: add InMemoryStage for dynamic stages
* flows: optionally allow empty flows from FlowPlanner
* providers/saml: update to authorization_flow
* sources/*: fix flow executor URL
* flows: fix pylint error
* flows: wrap responses in JSON object to easily handle redirects
* flow: dont cache plan's context
* providers/oauth: rewrite OAuth2 Provider to use flows
* providers/*: update docstrings of models
* core: fix forms not passing help_text through safe
* flows: fix HttpResponses not being converted to JSON
* providers/oidc: rewrite to use flows
* flows: fix linting
