MIP-2 New toml config file

Created by: jassak

Change config file to toml format. We import it from the top level of the code base and can access fields either with dictionary lookup or with attribute look up with tab completion.

from mipengine import config

setting = config.path.to.setting

Additionally, celery can now be started as usual, reading node_id from the config file, or as a python module getting the node_id as an extra argument.