Add a profile.d file for XDG Base Directory Specification

We declare most of the XDG environment variables for this spec:
- XDG_CONFIG_HOME
- XDG_DATA_HOME
- XDG_CONFIG_DIRS
- XDG_DATA_DIRS
- XDG_CACHE_HOME

I'm not yet sure what to do with XDG_RUNTIME_DIR.
Add python packages: dateutil, lxml, mechanize, requests