[FEAT] Replace nicepath by APISite.article_path
This replaces Family.nicepath and Family.nice_get_address and uses the info
from the siteinfo. Family.nicepath should be replaced by APISite.article_path
and Family.nice_get_address is already replaced by APISite.nice_get_address.
Only since MW version 1.16.0 'articlepath' is present in the siteinfo so it
parses it from the 'base' property and caches this inside the siteinfo.