Software (Backend): Asynchronous writing of the data

[mlej8]

Currently, the backend is doing a synchronous write for the collected data (e.g. the frontend is blocked until the backend is done writing BCI data). This slows down the collection process as the frontend needs to wait for the backend to be done writing before going on to the next collection. We can asynchronously write the data in the backend either using Celery Task Queue or asyncio. Need to investigate which solution would fit best in this scenario.

[mlej8]

On pause for now (low priority as we've reduced the collection period)