Add xrdcp option to pull_files.py

Adds option to use xrdcp to copy files on eos in pull_files.py

Changes:

• Check filesystem type field (new) is present in from_to_dict (either eos or cvmfs currently)
• If use_xrdcp is set: copy from cvmfs, xrdcp from eos

Users running without --use_xrdcp will see no change.

Tested on:

• Local machine with kinit, cvmfs, kinit + cvmfs
• lxplus

PS: /eos/cms/store/group/phys_higgs/cmshgg/earlyRun3Hgg/flow_corrections/2023_model is currently inaccessible through default copy (700 permissions), but available with --use_xrdcp ;)