feat: add basic support for "reports" feature

not much here yet, but trying to keep it lean and unopinionated since
implementations will probably vary a bit

tests/test_email.py

@@ -151,7 +151,7 @@ class TestEmailHandler(ConfigTestCase):
             self.assertEqual(len(modules), 1)
             self.assertIs(modules[0], mod)
 
-        # provider may specify modules as list
+        # provider may specify modules as string
         providers = {
             'wuttatest': MagicMock(email_modules='wuttjamaican.email'),
         }