support shenyu-admin expose prometheus metrics

[tomsun28]

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• You have read the contribution guidelines.
• You submit test cases (unit or integration tests) that back your changes.
• Your local test passed ./mvnw clean install -Dmaven.javadoc.skip=true.

Hi, this pr support shenyu-admin expose prometheus metrics. please take a review. thanks!

[tomsun28]

Use the grafana SpringBoot APM Dashboard, Dashboard ID is 2900.

[codecov-commenter]

Codecov Report

Merging #4336 (c5fa7dd) into master (11d542b) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #4336      +/-   ##
============================================
- Coverage     68.21%   68.19%   -0.02%     
+ Complexity     7484     7483       -1     
============================================
  Files          1020     1020              
  Lines         28870    28870              
  Branches       2577     2577              
============================================
- Hits          19693    19689       -4     
- Misses         7635     7638       +3     
- Partials       1542     1543       +1     

Impacted Files	Coverage Δ
...controller/ShenyuClientHttpRegistryController.java	63.63% <0.00%> (-18.19%)	⬇️
...ruptor/RegisterClientServerDisruptorPublisher.java	55.55% <0.00%> (-11.12%)	⬇️
...henyu/common/cache/MemorySafeWindowTinyLFUMap.java	73.33% <0.00%> (ø)

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[loongs-zhang]

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