fix scheduler and provide get-update-by-extender method

[miklezzzz]

Overview

1. Fixed some erroneous logic in the scheduler's logic when filtering modules by a terminator extender.
2. Provided a couple of methods to get info which extender actually enabled/disabled a module.

What this PR does / why we need it

1. To fix the aforementioned bug in the scheduler's logic.
2. To be able to reflect in modules' status why modules were enabled/disabled.

Special notes for your reviewer