docs: Fix Podman and Orbstack pages not found (#1678)

The underlined links currently point to 404 page. This PR fix them by
moving corresponding docs from `docs/contributing` to
`website/src/reference`.
<img width="3432" height="1936" alt="CleanShot 2025-09-16 at 23 52
27@2x"
src="https://github.com/user-attachments/assets/f8cf9f0c-ae2d-4196-a979-ee11c968d512"
/>

Author: manuzhang

CONTRIBUTING.md

@@ -103,8 +103,8 @@ cargo 1.69.0 (6e9a83356 2023-04-12)
 
 Currently, iceberg-rust uses Docker to set up environment for integration tests. Native Docker has some limitations, please check (https://github.com/apache/iceberg-rust/pull/748). Please use Orbstack or Podman.
 
-For MacOS users, you can install [OrbStack as a docker alternative](docs/contributing/orbstack.md).
-For Podman users, refer to [Using Podman instead of Docker](docs/contributing/podman.md)
+For MacOS users, you can install [OrbStack as a docker alternative](reference/orbstack.md).
+For Podman users, refer to [Using Podman instead of Docker](reference/podman.md)
 
 ## Build
 

website/src/SUMMARY.md

@@ -33,4 +33,5 @@
 # Reference
 
 - [Using Podman instead of Docker](./reference/podman.md)
-- [Setup GPG key](./reference/setup_gpg.md)
+- [OrbStack as a docker alternative](./reference/orbstack.md)
+- [Setup GPG key](./reference/setup_gpg.md)