support self-hosted gitlab URLs instead of having to fill out the long form

From question on forum -- CWL-viewer seems to have issues viewing a cwl workflows form gitlabs-- I replicated it as well.
Link: https://gitlab.inria.fr/capsid.public_codes/CroMaSt/-/blob/main/CroMaSt.cwl

Link to question:
https://gitlab.inria.fr/capsid.public_codes/CroMaSt/-/blob/main/CroMaSt.cwl

I went and found a another CWL workflow from gitlabs here -- https://gitlab.com/iidsgt/biocwl/-/blob/master/Workflows/Build-RNA-Indexes.cwl and it also couldn't render it -- so it might be a general issue with gitlab URLs.