[StaleIssueMarker] Refactor stale issues marking
[StaleIssueMarker] Refactor stale issues marking

Moves the logic for perform into a helper method.  In the future, this
is expected to have to make multiple queries to handle different parts
of the stale issue triage process as effeciently as possible.

ManageIQ/miq_bot,ManageIQ/miq_bot,ManageIQ/miq_bot,ManageIQ/miq_bot