[feature](struct-type) add children column when create table

[carlvinhust2012]

Proposed changes

1. this pr is used to add children column when create table.
2. after this change, we can get the children column info in ‘TCreateTabletReq’.

2022-12-15 10:38:06,485 INFO (agent-task-pool-0|128) [CreateReplicaTask.toThrift():198] column.getName()=s1, column.getType()=STRUCTf1:text,f2:bigint(20)
2022-12-15 10:38:06,485 INFO (agent-task-pool-0|128) [Column.toThrift():379] this.getDataType()=STRUCT, this.getType()=STRUCTf1:text,f2:bigint(20)
2022-12-15 10:38:06,486 INFO (agent-task-pool-0|128) [Column.toThrift():395] tColumn.getChildrenColumnSize()=2
2022-12-15 10:38:06,486 INFO (agent-task-pool-0|128) [CreateReplicaTask.toThrift():210] tColumn.getChildrenColumnSize()=2
2022-12-15 10:38:06,486 DEBUG (agent-task-pool-0|128) [AgentBatchTask.toAgentTaskRequest():200] TCreateTabletReq(tablet_id:695159, tablet_schema:TTabletSchema(short_key_column_count:1, schema_hash:1384684757, keys_type:DUP_KEYS, storage_type:COLUMN, columns:[TColumn(column_name:id, column_type:TColumnType(type:BIGINT, len:-1, index_len:8, precision:0, scale:0), is_key:true, is_allow_null:true, visible:true, col_unique_id:-1), TColumn(column_name:s1, column_type:TColumnType(type:STRUCT, len:-1, index_len:24, precision:-1, scale:-1), aggregation_type:NONE, is_key:false, is_allow_null:true, visible:true, children_column:[TColumn(column_name:field, column_type:TColumnType(type:STRING, len:2147483643, index_len:20, precision:0, scale:0), aggregation_type:NONE, is_allow_null:false), TColumn(column_name:field, column_type:TColumnType(type:BIGINT, len:-1, index_len:8, precision:0, scale:0), aggregation_type:NONE, is_allow_null:false)], col_unique_id:-1)], is_in_memory:false, delete_sign_idx:-1, sequence_col_idx:-1, sort_type:LEXICAL, sort_col_num:1, disable_auto_compaction:false), version:1, storage_medium:HDD, table_id:695157, partition_id:695156, storage_format:V2, tablet_type:TABLET_TYPE_DISK, compression_type:LZ4F, replica_id:695160, storage_policy:, enable_unique_key_merge_on_write:false)
2022-12-15 10:38:06,495 DEBUG (agent-task-pool-0|128) [AgentBatchTask.run():171] send task: type[CREATE], backend[10003], signature[695159]

Issue Number: close #xxx

Problem summary

Describe your changes.

Checklist(Required)

1. Does it affect the original behavior:
   • Yes
   • No
   • I don't know
2. Has unit tests been added:
   • Yes
   • No
   • No Need
3. Has document been added or modified:
   • Yes
   • No
   • No Need
4. Does it need to update dependencies:
   • Yes
   • No
5. Are there any changes that cannot be rolled back:
   • Yes (If Yes, please explain WHY)
   • No

Further comments

If this is a relatively large or complex change, kick off the discussion at dev@doris.apache.org by explaining why you chose the solution you did and what alternatives you considered, etc...

[cambyzju]

LGTM