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/google/uuid/version6.go

@@ -0,0 +1,56 @@
+// Copyright 2023 Google Inc.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package uuid
+
+import "encoding/binary"
+
+// UUID version 6 is a field-compatible version of UUIDv1, reordered for improved DB locality.
+// It is expected that UUIDv6 will primarily be used in contexts where there are existing v1 UUIDs.
+// Systems that do not involve legacy UUIDv1 SHOULD consider using UUIDv7 instead.
+//
+// see https://datatracker.ietf.org/doc/html/draft-peabody-dispatch-new-uuid-format-03#uuidv6
+//
+// NewV6 returns a Version 6 UUID based on the current NodeID and clock
+// sequence, and the current time. If the NodeID has not been set by SetNodeID
+// or SetNodeInterface then it will be set automatically. If the NodeID cannot
+// be set NewV6 set NodeID is random bits automatically . If clock sequence has not been set by
+// SetClockSequence then it will be set automatically. If GetTime fails to
+// return the current NewV6 returns Nil and an error.
+func NewV6() (UUID, error) {
+	var uuid UUID
+	now, seq, err := GetTime()
+	if err != nil {
+		return uuid, err
+	}
+
+	/*
+	    0                   1                   2                   3
+	    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+	   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	   |                           time_high                           |
+	   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	   |           time_mid            |      time_low_and_version     |
+	   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	   |clk_seq_hi_res |  clk_seq_low  |         node (0-1)            |
+	   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	   |                         node (2-5)                            |
+	   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	*/
+
+	binary.BigEndian.PutUint64(uuid[0:], uint64(now))
+	binary.BigEndian.PutUint16(uuid[8:], seq)
+
+	uuid[6] = 0x60 | (uuid[6] & 0x0F)
+	uuid[8] = 0x80 | (uuid[8] & 0x3F)
+
+	nodeMu.Lock()
+	if nodeID == zeroID {
+		setNodeInterface("")
+	}
+	copy(uuid[10:], nodeID[:])
+	nodeMu.Unlock()
+
+	return uuid, nil
+}