More detailed Datasouce routing support

[yuhuangbin]

present situation, We support multi data source routing through @DS annotation.
eg:

spring:
  datasource:
    dynamic:
      enabled: true
      primary: ds1
      datasource:
        ds1:
          driver-class-name: com.mysql.cj.jdbc.Driver
          url: jdbc:mysql://${ip}:${port}/${database}?useUnicode=true&characterEncoding=UTF-8
          username: xxx
          password: xxx
        ds2:
          driver-class-name: com.mysql.cj.jdbc.Driver
          url: jdbc:mysql://${ip}:${port}/${database}?useUnicode=true&characterEncoding=UTF-8
          username: xxx
          password: xxx

@DS("ds2")
@Service
public class UserServiceImpl implements UserService {
}

However, this method belongs to hard coding and cannot achieve dynamic configuration to specify data source routing switching. In some case, different data sources need to be specified for different methods under the same class. Refer: DynamicDatasourceNamedInterceptor, However, it has not been activated.
If it's worth it, I will fix it. Thanks

[gxmgxm]

您好 ，这里是高相猛，很高兴收到您的邮件 。