Look up major database resources in a before_request hook.

A `before_request` hook queries the database for portfolios, requests,
and task orders based on the route arguments. The resources are added as
attributes on `g`. The portfolio context processor and the access
decorator now rely on those resources being available on `g`.

WIP: find major resources in before_request hook, apply to g

WIP: use g.portfolio for portfolio context processor

WIP: the access decorator should rely on the resources being available on g

tests/test_access.py

@@ -78,9 +78,7 @@ def test_all_protected_routes_have_access_control(
     monkeypatch.setattr(
         "atst.domain.invitations.PortfolioInvitations._get", lambda *a: Mock()
     )
-    monkeypatch.setattr(
-        "atst.utils.context_processors.get_portfolio_from_context", lambda *a: None
-    )
+    monkeypatch.setattr("atst.app.assign_resources", lambda *a: None)
 
     # patch the internal function the access decorator uses so that
     # we can check that it was called