console namespace不存在时实例不显示

[wolfgangzhu]

Issue Description

Type: feature request

Describe what happened (or what feature you want)

在server端未配置namespace，此时服务注册时设置了一个随意的命名空间，服务注册成功，在console上的服务管理其实是无法找到该服务, 除非在console端配置，对使用者会造成疑惑。

Describe what you expected to happen

是否采用如下方式比较合适：
1）当服务配置的namespace（非默认的Public）未配置时，服务注册是否应注册失败
2）当服务配置的namespace（非默认的Public）未配置时，console会自动创建出namespace

How to reproduce it (as minimally and precisely as possible)

Tell us your environment

nacos 1.2.0

Anything else we need to know?

[chuntaojun]

Currently, for some reason, a namespace not created on the console cannot be displayed and persisted, which will be fixed in a future release

[KomachiSion]

duplicate with #4134