feat(crd): Refactor prometheus metrics

[dkarpele]

Prometheus metrics were successfully exported after refactoring

# HELP argocd_image_updater_applications_watched_total The total number of applications watched by Argo CD Image Updater
# TYPE argocd_image_updater_applications_watched_total gauge
argocd_image_updater_applications_watched_total 1
# HELP argocd_image_updater_images_errors_total Number of errors reported by Argo CD Image Updater
# TYPE argocd_image_updater_images_errors_total counter
argocd_image_updater_images_errors_total{application="argocd-image-updater-e2e/image-updater-001"} 0
# HELP argocd_image_updater_images_updated_total Number of images updates by Argo CD Image Updater
# TYPE argocd_image_updater_images_updated_total counter
argocd_image_updater_images_updated_total{application="argocd-image-updater-e2e/image-updater-001"} 2
# HELP argocd_image_updater_images_watched_total Number of images watched by Argo CD Image Updater
# TYPE argocd_image_updater_images_watched_total gauge
argocd_image_updater_images_watched_total{application="argocd-image-updater-e2e/image-updater-001"} 1
# HELP argocd_image_updater_k8s_api_errors_total The total number of Argo CD API requests resulting in error
# TYPE argocd_image_updater_k8s_api_errors_total counter
argocd_image_updater_k8s_api_errors_total 0
# HELP argocd_image_updater_k8s_api_requests_total The total number of Argo CD API requests resulting in error
# TYPE argocd_image_updater_k8s_api_requests_total counter
argocd_image_updater_k8s_api_requests_total 0