Upgrade to drive v0.25.3, replace MinIO with RustFS

- use rustfs instead of minio and provide migration script
- Schedule clean_pending_items/purge_deleted_items with celery beat
- Give celery workers the S3 access key secret
- Collabora admin access needs setting a password

Following the [C4DT AI Policy](https://git.coopcloud.tech/c4dt/ai-policy/src/branch/main/AI-POLICY.md):

 #LLM_vibe
 #LLM_model Claude Opus 5.5

- [x] I take full responsibility for this code
- [x] I understand every line of this code
- [x] I tested this code thoroughly on my own computer / servers
- [x] None of the commit messages were created using LLMs
- [x] I will participate in any discussion on my own and will not use an LLM for the discussion

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

onlyoffice-config.json.tmpl

@@ -1,4 +1,14 @@
 {
+    "services": {
+        "CoAuthoring": {
+            "ipfilter": {
+                "rules": [
+                    {"address": "{{ env "DOMAIN" }}", "allowed": true},
+                    {"address": "*", "allowed": true}
+                ]
+            }
+        }
+    },
     "wopi": {
         "enable": true,
         "host": "https://{{ env "ONLY_OFFICE_DOMAIN" }}",