Hook ISO XSLT into view service
add first pass at DCX XSLT. https://redmine.dataone.org/issues/7686
type the doctype="metadata" objects as "FGDC-STD-001-1998" formatId for rendering XSLT and for DataONE SystemMetadata.
redirect successful login to the registry page.
Stubs for 'metacatui' rendering. Initial target is to support Perl registry styling, but also general structured html views on metadata. https://projects.ecoinformatics.org/ecoinfo/issues/5951