在MySQL8.0默认状态下无法正常启动

- [ ] I have searched the [issues](https://github.com/seata/seata/issues) of this repository and believe that this is not a duplicate.

### Ⅰ. Issue Description
MySQL8默认需要区分表名大小写，启动时报以下警告：
```
global_table table or TRANSACTION_NAME column not found
```
分析源码后发现在LogStoreDataBaseDAO中，以下代码使用了大写字段名，而seata数据库中为小写字段。
```
private static final String TRANSACTION_NAME_KEY = "TRANSACTION_NAME";
```

### Ⅱ. 处理建议
将以上代码修改为：
```
private static final String TRANSACTION_NAME_KEY = "transaction_name";
```

Start in LogStoreDataBaseDAO and inspect the TRANSACTION_NAME_KEY constant against the lowercase schema names described in the issue. Verify the change with a MySQL 8.0 startup using the Seata database schema; done means startup no longer reports that global_table or the TRANSACTION_NAME column is missing.

Written by the indexing model from the issue text.