Reindex GitHub Events into maintainer inactivity data

[bshien]

Description

Reindexed GitHub Events stored in the metrics cluster into maintainer inactivity data for further display.

Issues Resolved

Part of #57

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[codecov]

Codecov Report

Attention: Patch coverage is 45.24887% with 121 lines in your changes missing coverage. Please review.

Project coverage is 77.04%. Comparing base (d8b52e6) to head (038014a).

Files with missing lines	Patch %	Lines
.../opensearchmetrics/metrics/MetricsCalculation.java	3.12%	62 Missing ⚠️
...hmetrics/metrics/maintainer/MaintainerMetrics.java	54.40%	52 Missing and 5 partials ⚠️
.../opensearchmetrics/model/maintainer/EventData.java	75.00%	0 Missing and 1 partial ⚠️
...searchmetrics/model/maintainer/MaintainerData.java	96.29%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main      #79      +/-   ##
============================================
- Coverage     82.98%   77.04%   -5.94%     
- Complexity      202      223      +21     
============================================
  Files            53       56       +3     
  Lines          1187     1407     +220     
  Branches         48       66      +18     
============================================
+ Hits            985     1084      +99     
- Misses          180      295     +115     
- Partials         22       28       +6     

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