Add Warm Disk Threshold Allocation Decider for Warm shards

[Gagan6164]

Description

This pull request introduces the WarmDiskThresholdDecider to handle the allocation and rebalancing of writable warm shards in OpenSearch. The current allocation logic for remote-capable shards is static and works well for searchable snapshot index shards, as their size remains constant. However, for writable warm shards, the size might not remain constant, and we might eventually exceed the total remote addressable size on a node.

Related Issues

Resolves #8535

Check List

• Functionality includes testing.
• API changes companion pull request created, if applicable.
• Public documentation issue/PR created, if applicable.

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✅ Gradle check result for 7e0b776: SUCCESS

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Codecov Report

Attention: Patch coverage is 76.22951% with 29 lines in your changes missing coverage. Please review.

Project coverage is 72.58%. Comparing base (560ac10) to head (4bd309b).
Report is 11 commits behind head on main.

Files with missing lines	Patch %	Lines
...g/allocation/decider/WarmDiskThresholdDecider.java	77.47%	13 Missing and 12 partials ⚠️
...ster/routing/allocation/DiskThresholdSettings.java	71.42%	2 Missing ⚠️
...uting/allocation/decider/DiskThresholdDecider.java	33.33%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #18082      +/-   ##
============================================
+ Coverage     72.56%   72.58%   +0.01%     
- Complexity    67261    67337      +76     
============================================
  Files          5476     5483       +7     
  Lines        310478   310776     +298     
  Branches      45133    45176      +43     
============================================
+ Hits         225313   225583     +270     
+ Misses        66840    66804      -36     
- Partials      18325    18389      +64     

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❕ Gradle check result for 4800c1d: UNSTABLE

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✅ Gradle check result for 4bd309b: SUCCESS