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/jsonpointer/.golangci.yml

@@ -0,0 +1,67 @@
+version: "2"
+linters:
+  default: all
+  disable:
+    - depguard
+    - funlen
+    - godox
+    - exhaustruct
+    - nlreturn
+    - nonamedreturns
+    - noinlineerr
+    - paralleltest
+    - recvcheck
+    - testpackage
+    - thelper
+    - tparallel
+    - varnamelen
+    - whitespace
+    - wrapcheck
+    - wsl
+    - wsl_v5
+  settings:
+    dupl:
+      threshold: 200
+    goconst:
+      min-len: 2
+      min-occurrences: 3
+    cyclop:
+      max-complexity: 20
+    gocyclo:
+      min-complexity: 20
+    exhaustive:
+      default-signifies-exhaustive: true
+      default-case-required: true
+    lll:
+      line-length: 180
+  exclusions:
+    generated: lax
+    presets:
+      - comments
+      - common-false-positives
+      - legacy
+      - std-error-handling
+    paths:
+      - third_party$
+      - builtin$
+      - examples$
+formatters:
+  enable:
+    - gofmt
+    - goimports
+    - gofumpt
+  exclusions:
+    generated: lax
+    paths:
+      - third_party$
+      - builtin$
+      - examples$
+issues:
+  # Maximum issues count per one linter.
+  # Set to 0 to disable.
+  # Default: 50
+  max-issues-per-linter: 0
+  # Maximum count of issues with the same text.
+  # Set to 0 to disable.
+  # Default: 3
+  max-same-issues: 0