Removed data_file, thermochimica_path, etc arguments from most functions, to...

Removed data_file, thermochimica_path, etc arguments from most functions, to allow more succint function calls, and instead exported them to a dedicated Config class so that these are class variables configured with an instance of tta, but they can of course be updated on the fly if they need to be changed, this is in line with intended/anticipated use.