Remove unused dependencies
Remove unused dependencies

1. libxml2 was used for the condor_ce_generator, which we no longer ship
2. The CE Registry pages now use Jinja2 templates (a Flask dep)

brianhlin/htcondor-ce,matyasselmeci/htcondor-ce,matyasselmeci/htcondor-ce,matyasselmeci/htcondor-ce,brianhlin/htcondor-ce,brianhlin/htcondor-ce