Make the transcribing calls async

[ABDreos]

Currently, the API calls for transcribing are done concurrently.

The solution should be done with an existing async library such as asyncio. However, other suggestions are welcomed.

Affected Packages

• bragir/transcription

Expected Benefits

• Improved Performance: Reduce the overhead associated with thread management and context switching.
• Scalability: Async can help with speed without a proportional increase in resource consumption.