kingdb support

[chncaesar]

Change Description

This pr adds support to Kingbase database v8, which is widely used in China. Kingbase is based on PostgreSQL , hence many classes in the plugin extends PostgreSQL.

Tests

The test is done against kingbase v8 KingbaseES V008R006C009B0014 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-28), 64-bit.

Here's the history table after running flyway baseline and flyway migrate

The plugin is being used in our internal kingbase and java applications.

Notes to use kingbase plugin

Configruation example

user=system
password=password
url=jdbc:kingbase8://192.168.1.1:54321/test_db
driver=com.kingbase8.Driver

Kingbase jdbc maven coordinates

<dependency>
    <groupId>cn.com.kingbase</groupId>
    <artifactId>kingbase8</artifactId>
    <version>8.6.0</version>
</dependency>

Please review, I'm looking forward to feedbacks.