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/policies/expression/models.py

@@ -2,13 +2,13 @@
 from django.db import models
 from django.utils.translation import gettext as _
 
-from passbook.policies.expression.evaluator import Evaluator
+from passbook.policies.expression.evaluator import PolicyEvaluator
 from passbook.policies.models import Policy
 from passbook.policies.types import PolicyRequest, PolicyResult
 
 
 class ExpressionPolicy(Policy):
-    """Jinja2-based Expression policy that allows Admins to write their own logic"""
+    """Implement custom logic using python."""
 
     expression = models.TextField()
 
@@ -16,12 +16,12 @@ class ExpressionPolicy(Policy):
 
     def passes(self, request: PolicyRequest) -> PolicyResult:
         """Evaluate and render expression. Returns PolicyResult(false) on error."""
-        evaluator = Evaluator()
+        evaluator = PolicyEvaluator(self.name)
         evaluator.set_policy_request(request)
         return evaluator.evaluate(self.expression)
 
     def save(self, *args, **kwargs):
-        Evaluator().validate(self.expression)
+        PolicyEvaluator(self.name).validate(self.expression)
         return super().save(*args, **kwargs)
 
     class Meta: