feat: add reusable GitHub Action to generate ImageCatalogs (#323)

Introduces a composite action that wraps `catalogs_generator.py` to
generate CloudNativePG ImageCatalog YAMLs from a container registry.
Supports multiple image types, distributions, and custom family prefixes.
Generates a `kustomization.yaml` for easy deployment of all catalogs.

Related to  cloudnative-pg/postgis-containers#100

Closes #324

Signed-off-by: Niccolò Fei <niccolo.fei@enterprisedb.com>
Signed-off-by: Gabriele Bartolini <gabriele.bartolini@enterprisedb.com>
Signed-off-by: Marco Nenciarini <marco.nenciarini@enterprisedb.com>
Co-authored-by: Gabriele Bartolini <gabriele.bartolini@enterprisedb.com>
Co-authored-by: Marco Nenciarini <marco.nenciarini@enterprisedb.com>

.github/workflows/catalogs.yml

@@ -15,6 +15,7 @@ jobs:
   update-catalogs:
     runs-on: ubuntu-24.04
     steps:
+      # TODO: remove this step once system images are EOL
       - name: Checkout code
         uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5
         with:
@@ -29,18 +30,15 @@ jobs:
           token: ${{ secrets.REPO_GHA_PAT }}
           ref: main
 
-      - name: Set up Python
-        uses: actions/setup-python@e797f83bcb11b83ae66e0230d6156d7c80228e7c # v6
-        with:
-          python-version: 3.13
-
-      - name: Install Python dependencies
-        run: |
-          pip install packaging==25.0 PyYAML==6.0.2
-
       - name: Generate catalogs
-        run: |
-          python postgres-containers/.github/catalogs_generator.py --output-dir artifacts/image-catalogs/
+        uses: ./postgres-containers/.github/actions/generate-catalogs
+        with:
+          output-dir: artifacts/image-catalogs/
+          registry: ghcr.io/cloudnative-pg/postgresql
+          family: postgresql
+          distributions: bullseye,bookworm,trixie
+          image-types: minimal,standard,system
+          regex: '(\d+)(?:\.\d+|beta\d+|rc\d+|alpha\d+)-(\d{12})'
 
       # TODO: remove this step once system images are EOL
       - name: Update legacy catalogs