Added pg_qualstats extension

Signed-off-by: Kristiansen, Erling Gustav Moland <Erling.Kristiansen@skatteetaten.no>

Author: egkristi

pg-qualstats/Dockerfile

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+# SPDX-FileCopyrightText: Copyright © contributors to CloudNativePG, established as CloudNativePG a Series of LF Projects, LLC.
+# SPDX-License-Identifier: Apache-2.0
+
+ARG BASE=ghcr.io/cloudnative-pg/postgresql:18-minimal-trixie
+FROM $BASE AS builder
+
+ARG PG_MAJOR
+ARG EXT_VERSION
+
+USER 0
+
+# Install extension via `apt-get`
+RUN apt-get update && apt-get install -y --no-install-recommends \
+      "postgresql-${PG_MAJOR}-pg-qualstats=${EXT_VERSION}"
+
+FROM scratch
+ARG PG_MAJOR
+
+# Licenses
+COPY --from=builder /usr/share/doc/postgresql-${PG_MAJOR}-pg-qualstats/copyright /licenses/postgresql-${PG_MAJOR}-pg-qualstats/
+
+# Libraries
+COPY --from=builder /usr/lib/postgresql/${PG_MAJOR}/lib/pg_qualstats* /lib/
+COPY --from=builder /usr/lib/postgresql/${PG_MAJOR}/lib/bitcode/ /lib/bitcode/
+
+# Share
+COPY --from=builder /usr/share/postgresql/${PG_MAJOR}/extension/pg_qualstats* /share/extension/
+
+USER 65532:65532

pg-qualstats/README.md

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+# pg_qualstats
+<!--
+SPDX-FileCopyrightText: Copyright © contributors to CloudNativePG, established as CloudNativePG a Series of LF Projects, LLC.
+SPDX-License-Identifier: Apache-2.0
+-->
+
+[pg_qualstats](https://github.com/powa-team/pg_qualstats) is a PostgreSQL
+extension that collects statistics about predicates (quals) found in
+`WHERE` clauses and `JOIN` conditions. It can be used to identify missing
+indexes and understand query workload patterns. For more information, see the
+[official documentation](https://powa.readthedocs.io/en/latest/components/pg_qualstats.html).
+
+## Usage
+
+The `pg_qualstats` extension must be loaded via `shared_preload_libraries`
+to hook into the query executor and collect predicate statistics.
+
+### 1. Add the pg_qualstats extension image to your Cluster
+
+Define the `pg-qualstats` extension under the `postgresql.extensions` section
+of your `Cluster` resource. For example:
+
+```yaml
+apiVersion: postgresql.cnpg.io/v1
+kind: Cluster
+metadata:
+  name: cluster-pg-qualstats
+spec:
+  imageName: ghcr.io/cloudnative-pg/postgresql:18-minimal-trixie
+  instances: 1
+
+  storage:
+    size: 1Gi
+
+  postgresql:
+    shared_preload_libraries:
+    - pg_qualstats
+    extensions:
+    - name: pg-qualstats
+      image:
+        # renovate: suite=trixie-pgdg depName=postgresql-18-pg-qualstats
+        reference: ghcr.io/cloudnative-pg/pg-qualstats:2.1.3-18-trixie
+```
+
+### 2. Enable the extension in a database
+
+You can install `pg_qualstats` in a specific database by creating or updating a
+`Database` resource. For example, to enable it in the `app` database:
+
+```yaml
+apiVersion: postgresql.cnpg.io/v1
+kind: Database
+metadata:
+  name: cluster-pg-qualstats-app
+spec:
+  name: app
+  owner: app
+  cluster:
+    name: cluster-pg-qualstats
+  extensions:
+  - name: pg_qualstats
+    # renovate: suite=trixie-pgdg depName=postgresql-18-pg-qualstats
+    version: '2.1.3'
+```
+
+### 3. Verify installation
+
+Once the database is ready, connect to it with `psql` and run:
+
+```sql
+\dx
+```
+
+You should see `pg_qualstats` listed among the installed extensions.
+
+## Contributors
+
+This extension is maintained by:
+
+- Erling Kristiansen (@egkristi)
+
+The maintainers are responsible for:
+
+- Monitoring upstream releases and security vulnerabilities.
+- Ensuring compatibility with supported PostgreSQL versions.
+- Reviewing and merging contributions specific to this extension's container
+  image and lifecycle.
+
+---
+
+## Licenses and Copyright
+
+This container image contains software that may be licensed under various
+open-source licenses.
+
+All relevant license and copyright information for the `pg_qualstats` extension
+and its dependencies are bundled within the image at:
+
+```text
+/licenses/
+```
+
+By using this image, you agree to comply with the terms of the licenses
+contained therein.

pg-qualstats/metadata.hcl

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+# SPDX-FileCopyrightText: Copyright © contributors to CloudNativePG, established as CloudNativePG a Series of LF Projects, LLC.
+# SPDX-License-Identifier: Apache-2.0
+metadata = {
+  name                     = "pg-qualstats"
+  sql_name                 = "pg_qualstats"
+  image_name               = "pg-qualstats"
+  licenses                 = ["PostgreSQL"]
+  shared_preload_libraries = ["pg_qualstats"]
+  extension_control_path   = []
+  dynamic_library_path     = []
+  ld_library_path          = []
+  bin_path                 = []
+  auto_update_os_libs      = false
+  required_extensions      = []
+  create_extension         = true
+
+  versions = {
+    bookworm = {
+      // renovate: suite=bookworm-pgdg depName=postgresql-18-pg-qualstats
+      "18" = "2.1.3-1.pgdg12+1"
+    }
+    trixie = {
+      // renovate: suite=trixie-pgdg depName=postgresql-18-pg-qualstats
+      "18" = "2.1.3-1.pgdg13+1"
+    }
+  }
+}