[Feature Request]: Support user defined functions

### Is there an existing issue for the same feature request?

- [X] I have checked the existing issues.

### Is your feature request related to a problem?

_No response_

### Describe the feature you'd like

CREATE
FUNCTION [IF NOT EXISTS] func_name ([func_parameter[,...]])
RETURNS type
routine_body

func_parameter:
param_name type

type:
Any valid MO data type

routine_body:
Valid SQL routine statement

- Compatible with MySQL syntax
- Support all MO data types as return values
- Support all MO process control statements

DROP FUNCTION [IF EXISTS] f func_name();

### Describe implementation you've considered

Update in 2024.01.15

The objective of this feature for 1.2 milestone is to gets a Python Machine Learning demo running. Anythings blocks this objective will be considered as feature or bug of UDF.

### Documentation, Adoption, Use Case, Migration Strategy

_No response_

### Additional information

_No response_