Move the config to external files and write-up a file loader.

Currently our `.json` config files are "inside" the code.  See `qgs/split_to_triple_store.py`

We should decouple this from the code, and allow for loading an external .json file with configs for repository creation. 
This way we will be able to test using different repository configs. (default.json, inference_on.json etc etc) 

This would look like:

`/configs/default.json` 
