Print a more helpful message if `TheSDK.config` is not found

[chiplet]

thesdk/thesdk/__init__.py

Line 120 in 07cf603

with open(CONFIGFILE,'r') as fid:

The current implementation throws an exception if the config file has not been generated.

FileNotFoundError: [Errno 2] No such file or directory: some/path/to/TheSDK.config

It would be more helpful if there would be a fatal log print that would instruct to run ./configure in the sdk project root.