Implement a circular beam for MeerKAT (L-band)
This implements the coefficients of the MeerKAT L-band beam.
Future task can be to distinguish the L-band from other bands. Also, more complex (accurate) models exist, but this is to get things started.
Corresponding WSClean ticket: https://gitlab.com/aroffringa/wsclean/-/merge_requests/554
Edited by Andre Offringa