create a Configuration

[basil96]

• Create a civilite.Configuration class.

• Storage schema:

  • use JSON for the config file.
  • Store the file as configuration.json in the user's home dir: os.path.expanduser('~').
  • Windows: .civilite subdirectory.
  • Linux: ~/.local/share/civilite directory.

• API: TBD. A simple dictionary based directly on JSON might suffice.

• As a start, move getCurrentSchedule() function out of schedule.py and into configuration.json.