Scan through active tasks to know which nvrs to check

Now you'll only have to do a GET on:

`/packages/get_latest_pkgs_from_brew/-1?secret_key=birdistheword`

Instead of hardcoding the task in the link:

`/packages/get_latest_pkgs_from_brew/-1?task_id=jb-eap-6-dot-3-dot-0&secret_key=birdistheword`

# Background
We have a cronjob that `GET` that link to schedule the check in ETT (yeah I know, we should use Sidekicq).

Before, we were hardcoding the task to run the check. Now the tasks are selected based on whether they are active or not.