docs: dev readme

DevREADME.md

@@ -0,0 +1,6 @@
+# 运行环境
+``` 
+ npm run dev
+ // 默认路径 http://localhost:2021/theme/
+ // 定制文件访问路径 http://localhost:2021/theme/?theme=http://localhost:2021/theme/src/packages/styles/variables-jdt.scss_source#/base
+```