Support the AUTO_RANDOM Field

[Icemap]

• Do only one thing
• Non breaking API changes
• Tested

What did this pull request do?

For this issue: #5977
Support the AUTO_RANDOM.

User Case Description

If you already deploy a TiDB at localhost:4000. You can use this code to test.

package main

import (
	"fmt"
	"gorm.io/driver/mysql"
	"gorm.io/gorm"
)

type Product struct {
	ID    uint `gorm:"primaryKey;autoRandom:true"`
	Code  string
	Price uint
}

func main() {
	db, err := gorm.Open(mysql.Open("root:@tcp(127.0.0.1:4000)/test"), &gorm.Config{})
	if err != nil {
		panic("failed to connect database")
	}

	db.AutoMigrate(&Product{})

	insertProduct := &Product{Code: "D42", Price: 100}

	db.Create(insertProduct)
	fmt.Printf("insert ID: %d, Code: %s, Prict: %d\n",
		insertProduct.ID, insertProduct.Code, insertProduct.Price)

	readProduct := &Product{}
	db.First(&readProduct, "code = ?", "D42") // find product with code D42

	fmt.Printf("read ID: %d, Code: %s, Prict: %d\n",
		readProduct.ID, readProduct.Code, readProduct.Price)
}

[Icemap]

@jinzhu PTAL

[Icemap]

Using new PR for avoiding interface changes.

• Support the AUTO_RANDOM Field mysql#104