Add catalog builder trait (#1261)

## Which issue does this PR close?

- Closes #1254 .

## What changes are included in this PR?

Add `CatalogBuilder` trait.

## Are these changes tested?

No, empty trait def.

Author: liurenjie1024

crates/iceberg/src/catalog/mod.rs

@@ -19,6 +19,7 @@
 
 use std::collections::HashMap;
 use std::fmt::{Debug, Display};
+use std::future::Future;
 use std::mem::take;
 use std::ops::Deref;
 
@@ -96,6 +97,18 @@ pub trait Catalog: Debug + Sync + Send {
     async fn update_table(&self, commit: TableCommit) -> Result<Table>;
 }
 
+/// Common interface for all catalog builders.
+pub trait CatalogBuilder: Default + Debug + Send + Sync {
+    /// The catalog type that this builder creates.
+    type C: Catalog;
+    /// Create a new catalog instance.
+    fn load(
+        self,
+        name: impl Into<String>,
+        props: HashMap<String, String>,
+    ) -> impl Future<Output = Result<Self::C>> + Send;
+}
+
 /// NamespaceIdent represents the identifier of a namespace in the catalog.
 ///
 /// The namespace identifier is a list of strings, where each string is a

crates/iceberg/src/lib.rs

@@ -64,10 +64,7 @@ pub use error::{Error, ErrorKind, Result};
 
 mod catalog;
 
-pub use catalog::{
-    Catalog, Namespace, NamespaceIdent, TableCommit, TableCreation, TableIdent, TableRequirement,
-    TableUpdate, ViewCreation,
-};
+pub use catalog::*;
 
 pub mod table;