Make `EXPLAIN STATEMENT` show logical and physical plans to run on regions

[NiwakaDev]

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What type of enhancement is this?

User experience

What does the enhancement do?

Greptimedb already supports distributed EXPLAIN ANALYZE STATEMENT(#3908).

However, EXPLAIN STATEMENT like EXPLAIN select * from system_metrics displays logical and physical plans only on the front side:

+---------------+--------------------------------------------------+
| plan_type     | plan                                             |
+---------------+--------------------------------------------------+
| logical_plan  | MergeScan [is_placeholder=false]                 |
| physical_plan | MergeScanExec: peers=[4398046511104(1024, 0), ]  |
+---------------+--------------------------------------------------+

I guess it's better to display logical and physical plans to run on regions for both developers and users, like this:

+---------------+--------------------------------------------------+
| plan_type     | plan                                             |
+---------------+--------------------------------------------------+
| logical_plan  | MergeScan [is_placeholder=false]                 |
|    		|	Projection: ~				   |
|     		|		 Filter: ~			   |
|       	|			 TableScan:                |
| physical_plan | MergeScanExec: peers=[4398046511104(1024, 0), ]  |
|			~					   |
+---------------+--------------------------------------------------+

Or

+---------------+------------------------------------------------------------------+
| stage         | plan_type     | plan                                             |
+---------------+------------------------------------------------------------------+
| 	0	| logical_plan  | MergeScan [is_placeholder=false]                 |
|    	1	|		|  Projection: ~		                   |
|     	1	|		|   Filter: ~	   		                   |
|       1	|		|    TableScan: demo                               |
| 	0	| physical_plan | MergeScanExec: peers=[4398046511104(1024, 0), ]  |
|	1	|	~	|				                   |
+---------------+------------------------------------------------------------------+

Implementation challenges

No response