[Feature] Support manage AI model in catalog

### Search before asking

- [x] I searched in the [issues](https://github.com/apache/paimon/issues) and found nothing similar.

### Motivation

In the multi-modal computing scenario of a data lakehouse, the metadata service needs to have AI model management capabilities. We hope that the Paimon catalog can provide support for this.

### Solution

The Paimon catalog provides interfaces for model creation/deletion/retrieval

### Anything else?

_No response_

### Are you willing to submit a PR?

- [ ] I'm willing to submit a PR!

Start by locating the Paimon catalog interfaces and existing catalog operations. The issue does not name files, tests, or an entry point, so first determine where model metadata belongs and how catalog creation, deletion, and retrieval are represented. Done means the catalog exposes and verifies all three model-management operations.

Written by the indexing model from the issue text.