Image Handler Refactor

[tjuav]

With the impending CV implementation, the current "download every image we don't have" implementation is not feasible.

Both server/handlers/image.py (GS) and tj-uav/FlightSoftware (FS) need to be updated with such an improved implementation.

Specifics of a sample implementation:

• The first request is made from GS->FS requesting for an update on images
• FS responds with an update on both total images taken and any objects identified (with locations and the image number they're from)
  • GS does not pull every image from FS
  • GS either pulls every image that contains an object, or the sections of these images that contain the object
  • Exact implementation is specific on the implementation of tj-uav/CV.
• GS displays downloaded images and their objects on the submissions page (Submissions Page Implementation #149)
  • Users can request to download specific images (or all images) with buttons
  • If only object-containing image sections are sent, users can request the full image

Related Issues:

• Copy on FS: GS Communication Refactor FlightSoftware#14
• Submissions page: Submissions Page Implementation #149
• Drop waypoints: Drop Waypoints #150