Dubbo 3 peripheral registration center, configuration center, metadata center expansion implementation

Dubbo 3 needs to support other registration centers, configuration centers, and metadata centers except Zookeeper and Nacos to facilitate users to implement different situations and need to be implemented based on dubbo-spi-extension.

Project requirements:
- Dubbo 3 supports registration centers such as consul, etcd3, eureka, redis, etc.
- Dubbo 3 supports configuration centers such as consul, apollo, etcd3
- Dubbo 3 supports metadata centers such as etcd3, redis, consul, apollo, etc.

Skills requirement:
- Proficiency in Java
- Familiar with Dubbo SPI mechanism
- Understand the use of consul, etcd3, redis, eureka and other components

Dubbo 3 需要支持除 Zookeeper 和 Nacos 外的其它注册中心、配置中心、元数据中心，方便用户落地不同的情况，需要基于 dubbo-spi-extension 实现。

产出要求：
- Dubbo 3 支持 consul、etcd3、eureka、redis 等注册中心
- Dubbo 3 支持 consul、apollo、etcd3 等配置中心
- Dubbo 3 支持 etcd3、redis、consul、apollo 等元数据中心

技术要求：
- 熟练使用 Java
- 熟悉 Dubbo SPI 机制
- 了解 consul、etcd3、redis、eureka 等组件对接使用