feat: add server shutdown util

[aaron-steinfeld]

Description

We are working on being good grpc users, and part of that is fully shutting down our servers. In most places today we either don't shut down, or don't wait for shutdown to complete due to some confusion in the various shutdown APIs. This new util makes it easy for servers to shutdown correctly.

Testing

Added UT, also tested locally with a service.

Checklist:

• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• Any dependent changes have been merged and published in downstream modules

[codecov]

Codecov Report

Merging #20 (aec0f66) into main (6f773e9) will decrease coverage by 0.07%.
The diff coverage is 72.00%.

@@             Coverage Diff              @@
##               main      #20      +/-   ##
============================================
- Coverage     72.92%   72.84%   -0.08%     
- Complexity       94      101       +7     
============================================
  Files            16       17       +1     
  Lines           277      302      +25     
  Branches         17       20       +3     
============================================
+ Hits            202      220      +18     
- Misses           61       66       +5     
- Partials         14       16       +2     

Flag	Coverage Δ
unit	72.84% <72.00%> (-0.08%)	⬇️

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Impacted Files	Coverage Δ
...ce/core/grpcutils/server/ServerManagementUtil.java	72.00% <72.00%> (ø)

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[github-actions]

Unit Test Results

12 files  +1  12 suites  +1   13s ⏱️ -1s
55 tests +2  55 ✔️ +2  0 💤 ±0  0 ❌ ±0 

Results for commit 3a96620. ± Comparison against base commit 6f773e9.