* [image-builder] Fix generate.sh
* [image-builder-api] Add use_retry_client to ResolveBaseImageRequest and BuildRequest
* [image-builder] Use req.GetUseRetryClient() instead of feature flag resolved on startup
[image-builder] Drop superfluous imports
[image-builder] Switch to github.com/hashicorp/go-retryablehttp, incl. better unit tests at orchestrator level!
* [server] Pass "useRetryClient" on all requests to image-builder