Usage stats: Tune collector execution startup and interval (#72688)
* Do not update statistics at service collector startup
* Configurable collector interval
* Introduce initial random delay
* Prevent reporting metrics until the stats have been collected
* Apply suggestion from code review
(cherry picked from commit afb59af79b)
Co-authored-by: Sofia Papagiannaki <1632407+papagian@users.noreply.github.com>