feat: add automatic mirroring to codeberg and gitlab

Signed-off-by: Goetz Goerisch <g.goerisch@vdw.de>

Author: GoetzGoerisch

.github/workflows/git-mirror.yml

@@ -0,0 +1,37 @@
+---
+name: Git Mirror
+# Mirror git repo to other sites
+
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - develop
+
+permissions:
+  contents: read
+
+jobs:
+  mirror:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+          persist-credentials: false
+
+      - name: "Sync repo codeberg"
+        uses: yesolutions/mirror-action@662fce0eced8996f64d7fa264d76cddd84827f33
+        with:
+          REMOTE: ${{ secrets.CODEBERG_URL }}
+          GIT_USERNAME: ${{ secrets.CODEBERG_USER }}
+          GIT_PASSWORD: ${{ secrets.CODEBERG_TOKEN }}
+
+      - name: "Sync repo gitlab"
+        uses: yesolutions/mirror-action@662fce0eced8996f64d7fa264d76cddd84827f33
+        with:
+          REMOTE: ${{ secrets.GITLAB_URL }}
+          REMOTE_NAME: gitlab
+          GIT_USERNAME: ${{ secrets.GITLAB_USER }}
+          GIT_PASSWORD: ${{ secrets.GITLAB_TOKEN }}