R1:1dd1237c9228

Remove "HeraldRepetitionPolicyConfig" and hide storage details inside HeraldRule

Summary:
Depends on D18925. Ref T13048. Currently, HeraldRule stores policies as integers (0 or 1) in the database.

The application tries to mostly use strings ("first", "every"), but doesn't do a good job of hiding the fact that the values are integers deeper in the stack. So we end up with a lot of code like this:

```lang=php
$stored_int_value = $rule->getRepetitionPolicy();
$equivalent_string =…