Delete Keycloak Helm chart and related files

This commit removes the entire Keycloak Helm chart and its related
resources from the repository. The decision to delete the chart was
necessary due to a strategic shift in managing our infrastructure,
which no longer requires the use of this particular Helm chart.

As part of this change, all relevant files including the
`.gitea/workflows/build-chart-keycloak.yml`, `README.md`,
`Chart.yaml`, `Chart.lock`, and all templates and values files
associated with the Keycloak chart have been deleted. This action
eliminates overhead and potential confusion related to outdated and
unnecessary configurations.

No direct replacements or migration paths are provided, and users
should seek alternative solutions for deploying Keycloak or related
functionalities. Future updates will focus on the remaining
components of our infrastructure.

.gitea/workflows/build-chart-keycloak.yml

@@ -1,43 +0,0 @@
-name: "Build Helm Chart"
-on:
-  push:
-    branches:
-      - main
-    paths:
-      - "charts/keycloak/Chart.yaml"
-
-jobs:
-  helm-package:
-    runs-on: ubuntu-latest
-    env:
-      APP: charts/keycloak
-    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