[feature request] Implement VisitableAdapter SourceGenerator

**What needs to be done?**
There needs to be some attribute like `[AutoVisitableAdapter]` that generates VisitableAdapter and VisitableAdapterFactory classes:
```cs
[AutoVisitableAdapter]
public record LinkedListNode<T>(T Data, LinkedListNode<T> Next)
{
    public bool HasNext() => Next != null;
}
```
**Additional context**
- https://github.com/Stepami/visitor-net?tab=readme-ov-file#adapter-usage