Suggestions for Sentinel dashboard

1.dashbord建议参照hystrix-dashboard或者spring-boot-admin的方式提供普通jar包，不要spring-boot-jar，这样方便大家集成扩展
2.dashbord建议支持context-path的配置，需要重写客户端与dashboard通信
3.建议支持从注册中心寻找已接入sentinel的客户端实例，类似spring-boot-admin的做法，双向接入都支持
4.如果是web应用，建议transport复用web体系，不要自建httpserver
5.将更多的扩展开放出来，方便大家自定义一些功能

Start by reviewing the Sentinel dashboard and client/dashboard communication entry points, then compare the requested packaging and integration approaches with Hystrix Dashboard and Spring Boot Admin. The issue lists five broad proposals—packaging, context-path support, registry discovery, web transport reuse, and extension points—so done is not defined and requires maintainers to decide the scope.

Written by the indexing model from the issue text.