[ISSUE #9415]update setExternalStorage logic，support more db check,add 8 count unit test

[wuchubuzai2018]

What is the purpose of the change

#9415
重写提交代码，合并冲突
Nacos多数据源通用适配改造点优化建议: 修改外置存储代码判断为通用反向逻辑
增加8个单元测试代码在2个类里面：
指定单例，未指定数据库，UseExternalDB是false
指定单例，指定数据库derby，UseExternalDB是false
指定单例，指定数据库为mysql， UseExternalDB是true
指定单例，指定数据库为其他， UseExternalDB是true
指定集群，未指定数据库，UseExternalDB是true，数据库类型是mysql
指定集群，指定数据库mysql，UseExternalDB是true，数据库类型是mysql
指定集群，指定数据库derby，UseExternalDB是false，数据库类型是derby
指定集群，指定数据库其他，UseExternalDB是true，数据库类型是其他

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• Write necessary unit-test to verify your logic correction, more mock a little better when cross module dependency exist. If the new feature or significant change is committed, please remember to add integration-test in test module.
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[codecov-commenter]

Codecov Report

Merging #9470 (e4fb973) into develop (5ea747b) will increase coverage by 0.14%.
The diff coverage is 33.33%.

Additional details and impacted files

@@              Coverage Diff              @@
##             develop    #9470      +/-   ##
=============================================
+ Coverage      47.51%   47.65%   +0.14%     
- Complexity      4568     4570       +2     
=============================================
  Files            856      856              
  Lines          28354    28355       +1     
  Branches        3195     3197       +2     
=============================================
+ Hits           13471    13512      +41     
+ Misses         13655    13615      -40     
  Partials        1228     1228              

Impacted Files	Coverage Δ
...cos/core/listener/StartingApplicationListener.java	47.42% <33.33%> (-1.54%)	⬇️
.../core/v2/event/publisher/NamingEventPublisher.java	76.25% <0.00%> (+1.25%)	⬆️
...cos/core/cluster/remote/ClusterRpcClientProxy.java	74.28% <0.00%> (+1.42%)	⬆️
...m/alibaba/nacos/core/remote/ConnectionManager.java	45.85% <0.00%> (+1.47%)	⬆️
...alibaba/nacos/client/config/impl/ClientWorker.java	55.40% <0.00%> (+4.63%)	⬆️
...m/alibaba/nacos/naming/misc/HttpClientManager.java	83.33% <0.00%> (+14.28%)	⬆️
...a/com/alibaba/nacos/core/remote/BaseRpcServer.java	89.47% <0.00%> (+26.31%)	⬆️

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[li-xiao-shuang]

Suggested change

	// 模拟设置环境05：指定集群，未指定数据库，UseExternalDB是true，数据库类型是mysql
	// 模拟设置环境05：指定集群，未指定数据库，UseExternalDB是true，数据库类型为""