Add 2.17.1 release notes (opensearch-project#16104) (opensearch-project#16105) (opensearch-project#16132)

(cherry picked from commit dff2184)
(cherry picked from commit af105b1)

Signed-off-by: Andriy Redko <andriy.redko@aiven.io>

Author: reta

release-notes/opensearch.release-notes-2.17.1.md

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+## 2024-10-01 Version 2.17.1 Release Notes
+
+## [2.17.1]
+### Added
+- Add path prefix support to hashed prefix snapshots ([#15664](https://github.com/opensearch-project/OpenSearch/pull/15664))
+- Memory optimisations in _cluster/health API ([#15492](https://github.com/opensearch-project/OpenSearch/pull/15492))
+
+### Dependencies
+
+### Changed
+
+### Deprecated
+
+### Removed
+
+### Fixed