Add command to setup either dcm2bids or heudiconv

[wasciutto]

Both dcm2bids and heudiconv have a setup function -

dcm2bids is dcm2bids_helper

• not currently implemented in clpipe

heudiconv's is essentially running heudiconv with the base template and no NIFTI conversion

• this one already exists as bids_conversion.dicom_to_nifti_to_bids_converter_setup()

User should be able to run something like clpipe convert2bids setup --dcm2bids to get the dcm2bids setup, for example

[wasciutto]

Under the 1.7.2 this would instead be a command like clpipe dicom setup_convert2bids