feat: add PostgreSQL Anonymizer container image

[pchovelon]

Extension

PostgreSQL Anonymizer is an extension to mask or replace personally identifiable information (PII) or commercially sensitive data from a Postgres database.

The project has a declarative approach of anonymization. This means you can declare the masking rules using the PostgreSQL Data Definition Language (DDL) and specify your anonymization policy inside the table definition itself.

Closes #345

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Contributor checklist

• My commits are signed off for DCO
  compliance (git commit -s).
• Experimental commits have been squashed into a single, well-formed commit.
• This PR targets the main branch of the upstream repository.
• A New Extension Proposal
  issue exists and is referenced via Closes #345 above.
• The commit message follows the format:
  feat: add `<extension-name>` container image.
• The Debian package was verified to exist in the main component on both
  Debian stable (trixie) and oldstable (bookworm) via apt search.
• The extension was scaffolded with task create-extension NAME=<ext> and all
  TODO comments in the generated files were resolved.
• metadata.hcl sets the correct package (full Debian version) and, when
  create_extension = true, the matching sql (catalog) version.
• create_extension is set correctly (false for PostgreSQL modules with
  no .control file, verified with dpkg -L).
• The renovate: annotations in metadata.hcl and README.md are present
  and intact (suite=, depName=, extractVersion=).
• Every component in the image is covered by a license on the
  CNCF Allowlist;
  SPDX licenses in metadata.hcl are accurate.
• task checks:all passes locally.
• Full E2E passes: task e2e:test:full TARGET="<extension-name>".
• README.md is complete and includes a working Cluster example (plus a
  Database example with CREATE EXTENSION when create_extension = true).
• An entry for the new extension folder was added to
  CODEOWNERS
  with the component owner's GitHub handle(s).
• A distribution-points entry for the new image was added under
  repository.release in
  SECURITY-INSIGHTS.yml.
• I confirm my commitment to maintain this extension on behalf of the
  CloudNativePG community.

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Maintainer review checklist

• The linked proposal issue is approved (label new-extension) and the
  Closes #<id> reference is correct.
• CI is green: the bake workflow built the new target for the full
  pgVersions × distributions × {amd64, arm64} matrix.
• DCO check passes and history is a single clean commit with the required
  feat: add ... message format.
• License compliance reviewed: all redistributed components (extension +
  transitive/system libs) are on the CNCF Allowlist; SPDX licenses match.
• metadata.hcl reviewed: package/sql versions, create_extension,
  runtime settings (shared_preload_libraries, *_path, env,
  required_extensions) and behavior flags are correct.
• renovate: annotations are intact so automated version PRs will track
  the package going forward.
• Dockerfile reviewed: final stage is FROM scratch and contains only the
  expected artifacts; the USER 65532:65532 directive matches the nonroot
  convention.
• E2E / Chainsaw tests pass: the extension is registered (when
  create_extension = true), or the Cluster reaches Healthy with the image
  mounted for preload-only modules.
• README.md is clear and its Cluster example (and Database example
  when create_extension = true) are valid.
• CODEOWNERS entry is present and the component owner(s) accept the
  long-term maintenance commitment.
• SECURITY-INSIGHTS.yml has a matching distribution-points entry for
  the new image.
• PR targets main and is ready to merge.