init master key automatically

[ylwu-amzn]

Description

[Describe what this change achieves]

Issues Resolved

[List any issues this PR will resolve]

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Commits are signed per the DCO using --signoff

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[codecov]

Codecov Report

Merging #1075 (d6fb41c) into 2.x (e3cb2e3) will increase coverage by 0.95%.
The diff coverage is 92.20%.

@@             Coverage Diff              @@
##                2.x    #1075      +/-   ##
============================================
+ Coverage     77.95%   78.90%   +0.95%     
- Complexity     2071     2116      +45     
============================================
  Files           167      167              
  Lines          8558     8618      +60     
  Branches        857      866       +9     
============================================
+ Hits           6671     6800     +129     
+ Misses         1503     1426      -77     
- Partials        384      392       +8     

Flag	Coverage Δ
ml-commons	78.90% <92.20%> (+0.95%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...ch/ml/engine/algorithms/remote/ConnectorUtils.java	68.75% <ø> (-2.27%)	⬇️
...n/java/org/opensearch/ml/model/MLModelManager.java	62.81% <ø> (+0.17%)	⬆️
.../org/opensearch/ml/settings/MLCommonsSettings.java	100.00% <ø> (ø)
.../opensearch/ml/engine/encryptor/EncryptorImpl.java	89.65% <83.33%> (+5.03%)	⬆️
...c/main/java/org/opensearch/ml/engine/MLEngine.java	66.25% <100.00%> (+2.50%)	⬆️
.../cluster/MLCommonsClusterManagerEventListener.java	80.00% <100.00%> (+0.58%)	⬆️
...n/java/org/opensearch/ml/cluster/MLSyncUpCron.java	78.74% <100.00%> (+3.05%)	⬆️
...c/main/java/org/opensearch/ml/indices/MLIndex.java	93.75% <100.00%> (+0.41%)	⬆️
...va/org/opensearch/ml/indices/MLIndicesHandler.java	69.73% <100.00%> (+0.81%)	⬆️
...rg/opensearch/ml/plugin/MachineLearningPlugin.java	99.00% <100.00%> (+<0.01%)	⬆️

... and 6 files with indirect coverage changes