optimize: automatic deletion of namingserver vgroup through Caffeine map

[ggbocoder]

• I have registered the PR changes.

Ⅰ. Describe what this PR did

Ⅱ. Does this pull request fix one issue?

Ⅲ. Why don't you add test cases (unit test/integration test)?

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[funky-eyes]

LGTM

[codecov]

Codecov Report

Attention: Patch coverage is 60.78431% with 20 lines in your changes missing coverage. Please review.

Project coverage is 52.27%. Comparing base (5601c36) to head (65152ed).
Report is 1 commits behind head on 2.x.

Files	Patch %	Lines
...ache/seata/namingserver/manager/NamingManager.java	60.71%	6 Missing and 5 partials ⚠️
.../src/main/java/org/apache/seata/server/Server.java	76.92%	3 Missing ⚠️
...common/metadata/namingserver/NamingServerNode.java	33.33%	2 Missing ⚠️
...ache/seata/namingserver/entity/bo/NamespaceBO.java	60.00%	1 Missing and 1 partial ⚠️
.../namingserver/NamingserverRegistryServiceImpl.java	0.00%	1 Missing ⚠️
...ver/storage/db/store/VGroupMappingDataBaseDAO.java	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##                2.x    #6770      +/-   ##
============================================
+ Coverage     52.15%   52.27%   +0.11%     
- Complexity     6289     6302      +13     
============================================
  Files          1064     1064              
  Lines         37194    37215      +21     
  Branches       4414     4417       +3     
============================================
+ Hits          19399    19454      +55     
+ Misses        15882    15837      -45     
- Partials       1913     1924      +11     

Files	Coverage Δ
.../namingserver/NamingserverRegistryServiceImpl.java	0.00% <0.00%> (ø)
...ver/storage/db/store/VGroupMappingDataBaseDAO.java	0.00% <0.00%> (ø)
...common/metadata/namingserver/NamingServerNode.java	36.66% <33.33%> (-0.38%)	⬇️
...ache/seata/namingserver/entity/bo/NamespaceBO.java	73.68% <60.00%> (-4.89%)	⬇️
.../src/main/java/org/apache/seata/server/Server.java	49.18% <76.92%> (+2.88%)	⬆️
...ache/seata/namingserver/manager/NamingManager.java	65.88% <60.71%> (-1.12%)	⬇️

... and 7 files with indirect coverage changes