task/ta22-22 -- Nparcel ftp.py module boilerplate

nparcel/ftp.py
* new module structure
Merge branch 'dev' into feature/us22
task/ta22-23 -- integrate config

nparcel/conf/npftp.conf
* sample config file used for testing

nparcel/ftp.py
* new methods set_config_file(), _parse_config() to manage the
  configuration items
Merge branch 'dev' into feature/us22
task/ta22-24 -- factor out BU_MAP to the config file

nparcel/conf/nparceld.conf
* new "file_bu" section to replace the BU_MAP global

nparcel/config.py
* update to support the new "file_bu" section

nparcel/loader.py
* replace BU_MAP global with configured "file_bu"

nparcel/loaderdaemon.py
* initialise a Loader() object with file_bu argument (taken from config)