Add Prow configuration for kubernetes/contributor-site Call for Help

Add approve plugin and trigger configuration for the Call for Help workflow.
Also add labels for call-for-help, sig-contribex-nco, and call-for-help-approved.
Add periodic job for Community Resilience Lottery Factor data update.

This enables the Community Resilience Dashboard feature where SIGs can
request assistance and get approved by SIG leads.

Author: TineoC

config/jobs/kubernetes/contributor-site/contributor-site-periodics.yaml

@@ -0,0 +1,38 @@
+periodics:
+  - name: pull-contributor-site-lottery-factor
+    cluster: eks-prow-build-cluster
+    annotations:
+      testgrid-dashboards: sig-contribex-contributor-website
+      testgrid-tab-name: pull-contributor-site-lottery-factor
+    decorate: true
+    extra_refs:
+      - repo: kubernetes/contributor-site
+        base_ref: master
+    spec:
+      containers:
+      - image: us-docker.pkg.dev/k8s-infra-prow/images/build/go-runner:v2.1.1
+        command:
+        - /bin/bash
+        - -c
+        - |
+          set -e
+          cd hack
+          go mod init hack || true
+          go mod tidy
+          go run gen-lottery-factor.go
+        env:
+        - name: GITHUB_TOKEN
+          valueFrom:
+            secretKeyRef:
+              name: github-token
+              key: token
+        resources:
+          limits:
+            cpu: "2"
+            memory: 2Gi
+          requests:
+            cpu: "1"
+            memory: 1Gi
+    cron: "0 0 * * 1"  # Every Monday at midnight UTC
+    labels:
+      preset-dind-enabled: "true"

config/prow/plugins.yaml

@@ -64,6 +64,7 @@ approve:
 - repos:
   - kubernetes/cluster-registry
   - kubernetes/contrib
+  - kubernetes/contributor-site
   - kubernetes/dashboard
   - kubernetes/dns
   - kubernetes/examples
@@ -155,6 +156,17 @@ approve:
   lgtm_acts_as_approve: false
   ignore_review_state: true
 
+trigger:
+  - repos:
+    - kubernetes/contributor-site
+    events:
+      - issue_comment
+      - issues
+    require_approval: true
+    approval_restriction: >-
+      approve from approvers in OWNERS file or
+      sig-contributor-experience-leads
+
 help:
   help_guidelines_url: https://www.kubernetes.dev/docs/guide/help-wanted/
   help_guidelines_summary: |
@@ -188,6 +200,10 @@ label:
     - ci-short
     - ci-extended
     - ci-full
+    # Call for Help labels for kubernetes/contributor-site
+    - call-for-help
+    - sig-contribex-nco
+    - call-for-help-approved
 
   restricted_labels:
     kubernetes/kubernetes: