add some data products autogenerated pages

docs/source/products/data/15_unitov_icme.rst

docs/source/products/data/16A_iaps_s1sep_list.rst

docs/source/products/data/16B_iaps_s2sep_list.rst

docs/source/products/data/20A_unical_indices.rst

docs/source/products/data/20B_unical_transport.rst

docs/source/products/data/20C_unical_SEP-spectra-Ace.rst

docs/source/products/data/20D_unical_SEP-spectra-BepC.rst

docs/source/products/data/51A_iaps_testpart-cubes.rst

docs/source/products/data/51B_iaps_testpart-images.rst

docs/source/products/data/57A_inaf_mercnafts.rst

docs/source/products/data/57B_inaf_mercna.rst