Support Microseconds in RBUS_DATETIME Type

[Sreedevi29]

Description: Currently, the RBUS_DATETIME type only supports second-level precision, because it internally uses a struct tm (or tm32) which does not store microseconds.

Components that generate timestamps with microsecond information (e.g., TR-143 DownloadDiagnostics/UploadDiagnostics BOMTime and EOMTime) cannot convey this sub-second data through the standard RBUS APIs.

Added teh changes to support microseconds in rbus_datetime type.

[github-actions]

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