Apriltag detection

[JGHartel]

This code provides implementations of

1. Apriltag detection from video (video/apriltags/detect_apriltags)
2. Estimation of camera position (video/apriltags/compute_camera_positions)
3. Filtering of these position estimates with a Kalman filter (preprocess/filter/smooth_camera_positions)
4. A tutorial trialling this functionality (source/tutorials/apriltag_detection)

All the functions are passed upstream to the recording level. The detection and computation create outputs in the form of json files which are checked when running the methods on recording level to avoid duplication of effort