Refactor PartitionsSaxHandler to use boost::json #2219

Job	Run time
PSV.Linux.Android.22.04	9m 1s
PSV.Win.VC2022	10m 12s
PSV.Clang.Format.Checker	33s
PSV.Commit.Checker	6s
PSV.iOS.MacOS14.Xcode15.ARM64	7m 29s
PSV.Linux.22.04.gcc11.Tests	13m 50s
PSV.Linux.22.04.gcc9.Tests.CodeCov	10m 49s
PSV.Linux.22.04.gcc11.OLP_SDK_ENABLE_DEFAULT_CACHE=OFF	2m 57s
PSV.MacOS15.Xcode16.ARM64	7m 3s
PSV.Linux.latest.gcc14.Tests	13m 49s
PSV.Linux.22.04.gcc9.Cpplint	8s
PSV.Linux.24.04.gcc13.Tests	13m 37s
PSV.Linux.22.04.gcc9.OLP_SDK_ENABLE_DEFAULT_CACHE=OFF	3m 20s
PSV.Linux.22.04.clang.Tests	14m 40s
PSV.Linux.latest.gcc14.OLP_SDK_ENABLE_DEFAULT_CACHE=OFF	2m 41s
PSV.iOS.MacOS15.Xcode26.ARM64	7m 20s
PSV.iOS.MacOS15.Xcode16.ARM64	7m 43s
	2h 5m 18s

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