Merge branch 'ns/core-fsyncmethod'

Replace core.fsyncObjectFiles with two new configuration variables, core.fsync and core.fsyncMethod. * ns/core-fsyncmethod: core.fsync: documentation and user-friendly aggregate options core.fsync: new option to harden the index core.fsync: add configuration parsing core.fsync: introduce granular fsync control infrastructure core.fsyncmethod: add writeout-only mode wrapper: make inclusion of Windows csprng header tightly scoped