jdcal,et_xmlfile,rcssmin: remove un-needed python packages

jdcal,et_xmlfile,rcssmin: remove un-needed python packages

This change removes a series of Python packages that are added to
seafile-seahub and are not needed.
After some investigation into seafile, there are no references for it.

These are some of the low-hanging fruits.
They're not used [not sure when they were], and these packages were born
out of some weird sprints somewhere and forgotten on web and left
un-maintained.

So, remove them.

Signed-off-by: Alexandru Ardelean <redacted>