Add support to upload snapshot shard blobs with hashed prefix

[ashking94]

Description

Following up from the RFC #15146, in this PR, we implement the same. More details can be seen in the RFC itself. Below is the summarised change -

1. Snapshot models each index as an IndexId. Multiple indexes can share the same IndexId even though they are fundamentally different. In this PR, we are updating the IndexId class to also hold information about the pathType.
2. The data corresponding to each of the IndexId is then stored in the index-N file (i.e. RepositoryData). Due to this, the metadata about the pathType is available at no additional cost during Snapshot operations like Creation, Deletion, Clone, cleanup.
3. To handle no zombie data due to the hashed prefix nature of the path, we also have introduced a snapshot_shard_paths file which keeps the data about the paths for all the shards for an IndexId. The same information is also used later during stale blob deletion. This file is cleaned up only when all the paths present in the file are deleted. Also, that the stale blob cleanup is done after the index-N file upload, which can lead to cases where the pathType information is no more available.

Related Issues

Resolves #15146

Check List

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

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[ashking94]

Flaky test #15117 seen. Build - https://build.ci.opensearch.org/job/gradle-check/45417/testReport/junit/org.opensearch.cluster.service/MasterServiceTests/testClusterStateUpdateLoggingWithDebugEnabled/

[github-actions]

❕ Gradle check result for e21d937: UNSTABLE

Please review all flaky tests that succeeded after retry and create an issue if one does not already exist to track the flaky failure.

[codecov]

Codecov Report

Attention: Patch coverage is 72.97297% with 90 lines in your changes missing coverage. Please review.

Project coverage is 72.00%. Comparing base (71d122b) to head (7c5b751).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...ch/repositories/blobstore/BlobStoreRepository.java	69.65%	62 Missing and 9 partials ⚠️
...a/org/opensearch/snapshots/SnapshotShardPaths.java	85.36%	3 Missing and 3 partials ⚠️
...mote/directory/RemoteSnapshotDirectoryFactory.java	0.00%	5 Missing ⚠️
...main/java/org/opensearch/repositories/IndexId.java	80.00%	1 Missing and 2 partials ⚠️
...va/org/opensearch/repositories/RepositoryData.java	83.33%	0 Missing and 2 partials ⚠️
...ava/org/opensearch/snapshots/SnapshotsService.java	60.00%	1 Missing and 1 partial ⚠️
...arch/index/recovery/RemoteStoreRestoreService.java	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #15426      +/-   ##
============================================
+ Coverage     71.99%   72.00%   +0.01%     
- Complexity    63700    63753      +53     
============================================
  Files          5248     5249       +1     
  Lines        297416   297643     +227     
  Branches      42984    43011      +27     
============================================
+ Hits         214113   214309     +196     
+ Misses        65776    65698      -78     
- Partials      17527    17636     +109     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[Bukhtawar]

Are existing ITs exercising these code paths or do we need to explicitly add them

[github-actions]

❌ Gradle check result for 1975071: null

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[ashking94]

❌ Gradle check result for 1975071: null

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

#14314

[github-actions]

✅ Gradle check result for 1975071: SUCCESS

[github-actions]

❌ Gradle check result for c04eb67: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[ashking94]

❌ Gradle check result for c04eb67: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

Flaky test - #14599

[github-actions]

✅ Gradle check result for c04eb67: SUCCESS

[github-actions]

✅ Gradle check result for fc82193: SUCCESS