1. create a project node to adjust the output column position when a mv is selected in olap scan node
2. pass SlotReference's column info when call Alias's toSlot() method
3. should compare plan's logical properties when compare two plans after rewrite
We have supportted array type default [], but when using lightweight schema Change to add column array type, query failed as follows:
Fix "array default type is unsupported" error.
Fix the default value filling assignment digit problem.
Fix _delete_sign_idx and _seq_col_idx when append_column or build_schema when load.
Tablet schema cache support recycle when schema sptr use count equals 1.
Add a http interface for flink-connector to sync ddl.
Improve tablet->tablet_schema() by max_version_schema.
