Add support for taskscaler scale throttle
## Description Update taskscaler to bring in support for scale throttling and exponential backoff delay. ## Proposal - [X] Add `scale_throttle.limit` and `scale_throttle.burst` to autoscaler options. (https://gitlab.com/gitlab-org/gitlab-runner/-/merge_requests/4722+) - [ ] Add documentation. <!-- Please paste a link of the related issues or/and merge requests -->
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