Implement autobackup-operator controllers, tests, CI and packaging

PVCs and CloudNativePG Clusters need S3 buckets and backup schedules
provisioned consistently. This operator watches the
backups.unkin.net/{schedule,destination} annotations on those objects and
provisions everything needed to back them up, with no new CRDs.

- Add a PVC controller that provisions cephrgw ObjectStoreUser/Bucket/BucketAccess,
  auto-generates a restic repo-password Secret and creates a k8up Schedule scoped
  to the PVC via spec.backup.volumes[].persistentVolumeClaim.claimName.
- Add a CNPG Cluster controller that provisions the same bucket stack, idempotently
  patches spec.backup.barmanObjectStore (leaving a user-set destinationPath alone
  with a Warning event) and creates a ScheduledBackup.
- Resolve destinations through a ConfigMap lookup table; requeue until the
  BucketAccess is Ready before creating schedule resources; own-reference created
  resources and retain bucket data by default.
- Add schedule-mapping helpers (k8up 5-field/shortcut pass-through, CNPG 6-field
  seconds-first) and deterministic, length-bounded name derivation.
- Add unit tests (schedule mapping, name derivation, destination resolution) and
  envtest controller tests for both paths, wiring the external CRDs into envtest.
- Add kubebuilder-generated RBAC, a Dockerfile (distroless/nonroot), Woodpecker
  lint/test/build pipelines and a tag-triggered image push to the artifactapi
  docker-internal registry, plus a version-bump Makefile and deploy manifests.

vendor/github.com/go-openapi/swag/netutils/net.go

@@ -0,0 +1,31 @@
+// SPDX-FileCopyrightText: Copyright 2015-2025 go-swagger maintainers
+// SPDX-License-Identifier: Apache-2.0
+
+package netutils
+
+import (
+	"net"
+	"strconv"
+)
+
+// SplitHostPort splits a network address into a host and a port.
+//
+// The difference with the standard net.SplitHostPort is that the port is converted to an int.
+//
+// The port is -1 when there is no port to be found.
+func SplitHostPort(addr string) (host string, port int, err error) {
+	h, p, err := net.SplitHostPort(addr)
+	if err != nil {
+		return "", -1, err
+	}
+	if p == "" {
+		return "", -1, &net.AddrError{Err: "missing port in address", Addr: addr}
+	}
+
+	pi, err := strconv.Atoi(p)
+	if err != nil {
+		return "", -1, err
+	}
+
+	return h, pi, nil
+}