policies/expression: migrate to raw python instead of jinja2 (#49)

* policies/expression: migrate to raw python instead of jinja2

* lib/expression: create base evaluator, custom subclass for policies

* core: rewrite propertymappings to use python

* providers/saml: update to new PropertyMappings

* sources/ldap: update to new PropertyMappings

* docs: update docs for new propertymappings

* root: remove jinja2

* root: re-add jinja to lock file as its implicitly required

passbook/core/migrations/0002_default_user.py

@@ -14,6 +14,7 @@ def create_default_user(apps: Apps, schema_editor: BaseDatabaseSchemaEditor):
     )
     pbadmin.set_password("pbadmin")  # nosec
     pbadmin.is_superuser = True
+    pbadmin.is_staff = True
     pbadmin.save()