feat: support setting field comments

[iTanken]

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

What did this pull request do?

Support to set the field comment according to the comment tag.

User Case Description

type TestTableFieldCommentUpdate struct {
	ID       string     `gorm:"column:id;primaryKey"`
	Name     string     `gorm:"column:name;comment:姓名"`
	Age      uint       `gorm:"column:age;comment:周岁"`
	Birthday *time.Time `gorm:"column:birthday;comment:生日"`
}

func (*TestTableFieldCommentUpdate) TableName() string { return "test_table_field_comment" }