docs: bifurcate documentation into user and admin sections (#38196)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

docs/admin_docs/index.md

@@ -0,0 +1,42 @@
+---
+title: Admin Documentation
+description: Administrator guides for installing, configuring, and managing Apache Superset
+---
+
+<!--
+Licensed to the Apache Software Foundation (ASF) under one
+or more contributor license agreements.  See the NOTICE file
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+"License"); you may not use this file except in compliance
+with the License.  You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
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+"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, either express or implied.  See the License for the
+specific language governing permissions and limitations
+under the License.
+-->
+
+# Admin Documentation
+
+This section contains documentation for system administrators and operators who deploy and manage Apache Superset installations.
+
+## What's in this section
+
+- **[Installation](/admin-docs/installation/installation-methods)** - Deploy Superset using Docker, Kubernetes, or PyPI
+- **[Configuration](/admin-docs/configuration/configuring-superset)** - Configure authentication, caching, feature flags, and more
+- **[Security](/admin-docs/security/)** - Set up roles, permissions, and secure your deployment
+
+## Related
+
+- **[Database Drivers](/user-docs/databases/)** - See User Docs for database connection setup (admins may need to install drivers)
+
+## Looking for something else?
+
+- **[User Documentation](/user-docs/)** - Guides for analysts and business users
+- **[Developer Documentation](/developer-docs)** - Contributing, extensions, and development guides