Auto compute angular resolution for SSKE
By now the user has to enter the device azimuthal resolution as parameter. This angular resolution is used to estimate the max expected depth gap between two successive firings, and to remove points on oblique planes. The default is set to Velodyne device at 5Hz.
With this MR, the angular resolution is automatically computed with the first frame of each Lidar device.
This adds a ~33% overhead for the keypoints extraction step.
This has been tested on Velodyne devices at 10 Hz and 20 Hz on strongest and dual return modes, and Ouster device at 10 Hz in strongest mode. It gave a result with a precision around 1e-3 degrees.
NOTE: it is necessary that the keypoints extraction is done in LIDAR coordinates system, with the device spinning around Z axis.
This MR is greatly inspired from !92 (closed) but simplifies the computation.