feat(shannon): to support executing SQL statement in javascript function

[ShannonBase]

Summary

Description for this feature.
Now that we have supported javascript language function in shaonnonbase. But, it can not run SQL statement. For example,

DELIMITER |
CREATE FUNCTION TestConn() RETURNS INT
LANGUAGE JAVASCRIPT AS 
BEGIN
    const mysql = require('mysql');

    const connection = executeSQL("select * from table1 where col1='a'");

    return 0;
END|

We want to execute a SQL statement in javascript function.

[ShannonBase]

This issue will be supported when #277 was done.