[opt](information_schema) support information_schema in external catalog (#28919)

Add `information_schema` database for all catalog.
This is useful when using BI tools to connect to Doris,
the tools can get meta info from `information_schema`.

This PR mainly changes:

1. There will be a `information_schema` db in each catalog.
2. Each `information_schema` db only store the meta info of the catalog it belongs to.
3. For `information_schema`, the `TABLE_SCHEMA` column's value is the database name.
4. There is a new global variable `show_full_dbname_in_info_schema_db`, default is false, if set to true,
    The `TABLE_SCHEMA` column's value is the like `ctl.db`, because:

	When connect to Doris, the `database` info in connection url will be: `xxx?db=ctl.db`.
	
	And then some BI will try to query `information_schema` with sql like:
	
	`select * from information_schema.columns where TABLE_SCHEMA = "ctl.db"`
	
	So it has to be format as `ctl.db`
	
	eg, the `information_schema.columns` table in external catalog `doris` is like:
	
	```
	mysql> select * from information_schema.columns limit 1\G
	*************************** 1. row ***************************
	           TABLE_CATALOG: doris
	            TABLE_SCHEMA: doris.__internal_schema
	              TABLE_NAME: column_statistics
	             COLUMN_NAME: id
	        ORDINAL_POSITION: 1
	          COLUMN_DEFAULT: NULL
	             IS_NULLABLE: NO
	               DATA_TYPE: varchar
	CHARACTER_MAXIMUM_LENGTH: 4096
	  CHARACTER_OCTET_LENGTH: 16384
	       NUMERIC_PRECISION: NULL
	           NUMERIC_SCALE: NULL
	      DATETIME_PRECISION: NULL
	      CHARACTER_SET_NAME: NULL
	          COLLATION_NAME: NULL
	             COLUMN_TYPE: varchar(4096)
	              COLUMN_KEY:
	                   EXTRA:
	              PRIVILEGES:
	          COLUMN_COMMENT:
	             COLUMN_SIZE: 4096
	          DECIMAL_DIGITS: NULL
	   GENERATION_EXPRESSION: NULL
	                  SRS_ID: NULL
	```
	
6. Modify the behavior of

	- show tables
	- shwo databases
	- show columns
	- show table status

	The above statements may query the `information_schema` db if there is `where` predicate after them

be/src/exec/schema_scanner.cpp

@@ -44,6 +44,7 @@
 #include "exec/schema_scanner/schema_views_scanner.h"
 #include "olap/hll.h"
 #include "runtime/define_primitive_type.h"
+#include "util/string_util.h"
 #include "util/types.h"
 #include "vec/columns/column.h"
 #include "vec/columns/column_complex.h"
@@ -312,4 +313,12 @@ Status SchemaScanner::fill_dest_column_for_range(vectorized::Block* block, size_
     return Status::OK();
 }
 
+std::string SchemaScanner::get_db_from_full_name(const std::string& full_name) {
+    std::vector<std::string> part = split(full_name, ".");
+    if (part.size() == 2) {
+        return part[1];
+    }
+    return full_name;
+}
+
 } // namespace doris