The creation of hudi and iceberg table is disallowed since v1.2.
All these features are covered by hudi/iceberg catalog.
We should remove the code in v2.1
The PR mainly changes:
1. remove the code of hudi/iceberg external table.
2. remove code of iceberg database.
3. disallowed hive external table's creation.
4. disabled odbc,mysql,broker external table by default, and add FE config `disable_odbc_mysql_broker_table` to control it