Unnecessary class: com.alibaba.nacos.common.utils.Objects

[SunJiFengPlus]

Issue Description

com.alibaba.nacos.common.utils.Objects and java.util.Objects have most of the same code.

The only difference is that com.alibaba.nacos.common.utils.Objects::requireNonNullElse, I did a global search and there was no other place to use it, Optional can be instead of this method.

So I wonder if I can delete it.

if it pass, i can do this.

[KomachiSion]

I think the com.alibaba.nacos.common.utils.Objects is copy from jdk. Because before nacos 2.0, the nacos-client is compile with jdk1.6. java.util.Objects add since 1.7. So add this Util to use.

Now we can replace back to jdk's util and remove old util.