(PXP-6544) Pelican-export allows client to specify the root node

[mpingram]

Link to Jira: PXP-6544
Link to design doc: https://docs.google.com/document/d/12FkAYOpDuSdQScEgYBxXsPUdm8GUuUZgD6xU7EQga5A/edit#
Link to related portal PR: uc-cdis/data-portal#729

New Features

• Pelican-export job now allows client to specify the root node of a pfb when dispatching a job, allowing clients to export PFBs of entities that are not on the $ROOT_NODE environment variable. This allows for exporting of data file PFBs, so long as the data files are all on the same root node.
• The pelican-export algorithm's extra_nodes input can now be configured by $EXTRA_NODES environment variable. The old behavior of including reference_file and reference_file_index for BDCat exports is still there for backwards compatibility.

Breaking Changes

Bug Fixes

Improvements

Dependency updates

Deployment changes