Add creation of plots to the calibrate workflow

bin/plotrapthor

docs/source/products.rst

rapthor/lib/facet.py

rapthor/lib/parset.py

rapthor/operations/calibrate.py

rapthor/operations/image.py

rapthor/pipeline/parsets/calibrate_pipeline.cwl

rapthor/pipeline/parsets/image_pipeline.cwl

rapthor/pipeline/parsets/image_sector_pipeline.cwl

rapthor/pipeline/steps/make_region_file.cwl

rapthor/pipeline/steps/plot_solutions.cwl

rapthor/scripts/calculate_bl_lengths.py

rapthor/scripts/compare_image_stats.py

rapthor/scripts/flag_residual_gains.py

rapthor/scripts/pre_average_freq.py

rapthor/scripts/pre_average_time.py

rapthor/scripts/reset_h5parm.py

rapthor/scripts/reweight.py