WIP Use Flows for Sources and Providers (#32)

* 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

passbook/providers/oidc/auth.py

@@ -10,6 +10,8 @@ from structlog import get_logger
 
 from passbook.audit.models import Event, EventAction
 from passbook.core.models import Application, Provider, User
+from passbook.flows.planner import FlowPlan
+from passbook.flows.views import SESSION_KEY_PLAN
 from passbook.policies.engine import PolicyEngine
 
 LOGGER = get_logger()
@@ -46,7 +48,7 @@ def check_permissions(
     LOGGER.debug(
         "Checking permissions for application", user=user, application=application
     )
-    policy_engine = PolicyEngine(application.policies.all(), user, request)
+    policy_engine = PolicyEngine(application, user, request)
     policy_engine.build()
 
     # Check permissions
@@ -56,9 +58,10 @@ def check_permissions(
             messages.error(request, policy_message)
         return redirect("passbook_providers_oauth:oauth2-permission-denied")
 
+    plan: FlowPlan = request.session[SESSION_KEY_PLAN]
     Event.new(
         EventAction.AUTHORIZE_APPLICATION,
         authorized_application=application,
-        skipped_authorization=False,
+        flow=plan.flow_pk,
     ).from_http(request)
     return None