Add CRUD for Cluster and Namespace Entity

add app CRUD logic in admin service

Use HttpURLConnection and gson to remove Spring and Jackson dependencies

refactor config client - add config repository

remove auto mvc

Add JPA lifecycle annotation & Integrate env in portal

文本view 视图切换。修改过的key可以查看旧值

Add local cache file persistence

use default namespace for demo

client rewrite using unidal

portal can load data

Integrate EurekaServer into AdminSerivce Test, and update sample test…

portal V2

Force REST return json format

rewriting config client, this is an incomplete version

Fix AdminService bugs

Update entity model & service

Entity and Biz Refactor