Merge changes from 2.7 branch
add sample DCX document for debug comparison. https://redmine.dataone.org/issues/7829
render temporal periods and single dates. https://redmine.dataone.org/issues/7686
surround onedcx metdata display in form-horizontal section for more consistent layout with other metadata standards. https://redmine.dataone.org/issues/7686
place bounding coordinates in controls-well. https://redmine.dataone.org/issues/7686
consolidate online access section. format xsl whitespace
add creators and online access sections for DCX. https://redmine.dataone.org/issues/7686
add first pass at DCX XSLT. https://redmine.dataone.org/issues/7686