Add workflow for building and pushing the python-builder image, it's used in other workflows

Author: vtaskow

.github/workflows/python-builder.yml

@@ -0,0 +1,42 @@
+name: Build & Push the Python Builder Image
+
+on:
+  workflow_dispatch:
+    inputs:
+      docker-tag:
+        description: 'Docker tag for push (e.g. 2.0.0)'
+        required: true
+
+env:
+  GOLANG_VERSION: 1.24.7
+
+jobs:
+  operator:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v3
+        with:
+          go-version: ${{ env.GOLANG_VERSION }}
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Login to DockerHub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+
+      - name: Set default docker tag for builds from master
+        id: docker-tag
+        run: |
+          USER_INPUT="${{ github.event.inputs.docker-tag }}"
+          echo "value=${USER_INPUT:-latest}" >> $GITHUB_OUTPUT
+
+      - name: Build and push
+        working-directory: ./python-builder/
+        run: |
+          make DOCKER_IMAGE_VERSION=${{ steps.docker-tag.outputs.value }} build_docker_image
+          make DOCKER_IMAGE_VERSION=${{ steps.docker-tag.outputs.value }} push_to_registry