Fix/Separate bin file

[xinyuli1204]

Context or motivation

Current two sensors will store in single bin file

Goal

we want save one in each

TODO

• [x] separate them and store one in each bin file,
• [x] add prefix to determine filename (eg. prefix = "sensor_0" ---> bin file name: sensor_0.bin)

[xinyuli1204]

resolved in https://github.com/fixstars/ion-kit/pull/265