Description of proposed changes

• utils.utils0.get_lat_lon(): add ystep and xstep for more flexible output

• utils.utils.py: add prepare_geo_los_geometry() from solid_earth_tides.py for easy re-use.

• bulk_plate_motion.py:

  • support radar-coord geometry input via resample object to radar-code the PMM output
  • refactor pmm2enu_at()
  • replace scipy.interpolate with skimage.transform.resize
  • use ut.get_lat_lon() for coarse grid preparation
  • use ut.prepare_geo_los_geometry() and simplify the post-handling for unit and no-data value
  • remove the obsolete interp_2d3l(), get_geobox_width_length()
  • remove MORVEL56 example cmd, to avoid potential confusion
  • replace BulkPlateMotion.h5 with ITRF14.h5 for the default output file name. This may change in the future to other PMM names once they are auto determined with values auto grabbed.
  • use pmm internally in the code

Reminders

• Pass Codacy code review (green)
• Pass Circle CI test (green)
• If modifying functionality, describe changes to function behavior and arguments in a comment below the function declaration.
• If adding new functionality, add a detailed description to the documentation and/or an example.