1. Add support for Doris to parse ES date field without time zone info. eg: `2023-04-17T23:01:18.151`, this time will be treated as UTC time, since ES assumes that the time zone for time fields without time zones is UTC.
2. Change local time zone convertion from system local time zone to session variable time zone.
Issue Number: close#24315
The root cause of this issue is that Elasticsearch's long type allows inserting floats and strings. Doris did not handle these cases when doing type conversion. The current strategy is to take the integer before the decimal point if a float or string is found.
sort out the test cases of external table.
After modify, there are 2 directories:
1. `external_table_p0`: all p0 cases of external tables: hive, es, jdbc and tvf
2. `external_table_p2`: all p2 cases of external tables: hive, es, mysql, pg, iceberg and tvf
So that we can run it with one line command like:
```
sh run-regression-test.sh --run -d external_table_p0,external_table_p2
```
