Feature/save raw data

[Romasav]

Summary

• Implemented the functionality to save raw data received from the device to persistent storage.

Changes

• Added a DataStorageRepo interface and its implementation to handle saving raw data.
• Integrated the saving logic into the existing data stream processing pipeline.
• Added methods to start and stop data recording, ensuring raw data is only saved during active recording sessions.
• Updated the GetProcessedDataStreamUseCase to include the saving of raw data.

Testing

• Verified that raw data is saved correctly to the application documents directory.
• Tested start and stop recording functionality to ensure data is only saved when recording is active.