Remove hard-coded configuration in RDF-Viz

[Perevalov]

Move all hard-coded configuration parameters (e.g. triplestore URL, login, password) to a configuration file. Example of a hard-coded parameter (triplestore URL): https://github.com/jayeshdesai4520/chatbot-ng-internal/blob/6833f4470d5faefca812534b2737a62e27fd5c96/RDF-Visualization/app.py#L12

Please, refer to this library for creating and reading configuration file: https://docs.python.org/3/library/configparser.html

DoD:

• [x] A configuration file structure is created
• [x] All the configuration parameters are moved to the config file