Image Compression takes excessive time and stalls /targets/all route #384

🐛 Bug

When /targets/all is called, all available images are compressed synchronously before being encoded to JSON

To Reproduce

Steps to reproduce the behavior:

1. Wait for the plane to enter FlySearch and get some detections
2. Choose the reports page and set the interval to a positive number
3. Observe ~9 seconds delay per image sent

Expected behavior

The route should finish faster (ideally 3-4 seconds max for multiple images)

Additional context

Here are some of the possible solutions we discussed:

• Replace the compression algorithm with a faster alternative
  • Maybe. look into a CUDA acceleration?
• Move the compression (and maybe b64 encoding) step to the end of the cv pipeline instead of in the http route
• Crop images to only send the bounding box and some surrounding area.