feat(storage): add Prometheus histogram metric for new blob uploads

mentioned in commit 99a376f9

mentioned in issue #488 (closed)

mentioned in merge request gitlab-org/build/CNG!825 (merged)

mentioned in merge request gitlab-com/gl-infra/k8s-workloads/gitlab-com!1356 (merged)

mentioned in merge request gitlab-org/charts/gitlab!2271 (merged)

mentioned in merge request gitlab-com/gl-infra/k8s-workloads/gitlab-com!1357 (merged)

mentioned in merge request omnibus-gitlab!5827 (merged)

mentioned in merge request gitlab-development-kit!2385 (merged)