Fix/Separate gendc bin file

[xinyuli1204]

Context or motivation

Similar as https://github.com/fixstars/ion-kit/issues/266 Gendc buffer from two sensors will split and store into two 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 = "gendc_0" ---> bin file name: gendc_0.bin)

[xinyuli1204]

resolve in https://github.com/fixstars/ion-kit/pull/268