Add Helm chart for calibre-web deployment

This commit introduces a new Helm chart for deploying calibre-web
on Kubernetes. The chart includes essential templates for
deployment, service, ingress, and persistent volume claims, along
with default values configured in a `values.yaml` file.

The addition of the Helm chart enables easier deployment and
management of calibre-web, allowing users to customize settings
like the replica count, image settings, service type, and storage
options through the `values.yaml`. A GitHub Actions workflow
(`build-chart-calibre-web.yml`) is also included to automate the
packaging and uploading of the Helm chart upon updates to the
main branch.

The structure and organization of the templates adhere to Helm
best practices, ensuring compatibility and ease of use. There are no
breaking changes associated with this addition, but users should
review the `values.yaml` for configurable options.

.gitea/workflows/build-chart-calibre-web.yml

@@ -0,0 +1,43 @@
+name: "Build Helm Chart"
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - "charts/calibre-web/Chart.yaml"
+
+jobs:
+  helm-package:
+    runs-on: ubuntu-latest
+    env:
+      APP: charts/calibre-web
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Set Helm Chart App Name and Version
+        id: get_version
+        run: |
+          APP_NAME=$(grep -oP '(?<=^name: ).*' ${{ env.APP }}/Chart.yaml)
+          echo "Helm Chart App Name: $APP_NAME"
+          echo "::set-output name=app::$APP_NAME"
+
+          CHART_VERSION=$(grep -oP '(?<=^version: ).*' ${{ env.APP }}/Chart.yaml)
+          echo "Helm Chart version: $CHART_VERSION"
+          echo "::set-output name=tag::$CHART_VERSION"
+
+      - name: Setup Helm
+        run: |
+          #curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash
+          curl -kSso /usr/local/bin/helm https://debmirror.cooltux.net/helm-v3.18.4 && chmod +x /usr/local/bin/helm
+          helm version
+
+      - name: Package Helm Chart
+        run: |
+          helm dependency update ${{ env.APP }}
+          helm lint ${{ env.APP }}
+          helm package ${{ env.APP }}
+
+      - name: Upload Helm Package to repo
+        run: |
+          curl --user ${{ secrets.USER }}:${{ secrets.TOKEN }} -X POST --upload-file ./${{ steps.get_version.outputs.app }}-${{ steps.get_version.outputs.tag }}.tgz ${{ vars.HELMREGISTRY }}/api/packages/${{ vars.OWNER }}/helm/api/charts