[feat](maxcompute) support create/drop table operations (#60702)

### What problem does this PR solve?

Support DDL operations (CREATE TABLE and DROP TABLE) for MaxCompute
external catalog in Doris. This enables users to create and drop
tables directly in MaxCompute through Doris SQL interface.

  Example usage:

  1. Basic table creation:
 
     CREATE TABLE test_table (
         id INT,
         name STRING,
         age INT
     );

  3. Table with partition and distribution:
     CREATE TABLE test_table_partitioned (
         id INT,
         name STRING,
         value INT,
         ds STRING
     )
     PARTITION BY (ds)()
     DISTRIBUTED BY HASH(id) BUCKETS 8;

Key changes:
- Add MaxComputeMetadataOps class to handle table creation and deletion
- Extend MaxComputeExternalCatalog to support metadata operations
- Add column validation and type mapping for MaxCompute
- Add regression tests for create/drop table operations

Author: morningman

fe/fe-core/src/main/java/org/apache/doris/datasource/maxcompute/MaxComputeExternalCatalog.java

@@ -24,6 +24,7 @@
 import org.apache.doris.datasource.ExternalCatalog;
 import org.apache.doris.datasource.InitCatalogLog;
 import org.apache.doris.datasource.SessionContext;
+import org.apache.doris.datasource.operations.ExternalMetadataOperations;
 import org.apache.doris.datasource.property.constants.MCProperties;
 
 import com.aliyun.odps.Odps;
@@ -231,13 +232,20 @@ protected void initLocalObjectsImpl() {
         boolean enableNamespaceSchema = Boolean.parseBoolean(
                 props.getOrDefault(MCProperties.ENABLE_NAMESPACE_SCHEMA, MCProperties.DEFAULT_ENABLE_NAMESPACE_SCHEMA));
         mcStructureHelper = McStructureHelper.getHelper(enableNamespaceSchema, defaultProject);
+
+        metadataOps = ExternalMetadataOperations.newMaxComputeMetadataOps(this, odps);
     }
 
     public Odps getClient() {
         makeSureInitialized();
         return odps;
     }
 
+    public McStructureHelper getMcStructureHelper() {
+        makeSureInitialized();
+        return mcStructureHelper;
+    }
+
     protected List<String> listDatabaseNames() {
         makeSureInitialized();
         return mcStructureHelper.listDatabaseNames(getClient(), getDefaultProject());