Update database configurations

[KathiEsterl]

When initiating the process for the first time, the user is prompted to provide database connection details—even when using 'oep' to import the data model from the OEP.

This results from the initialization process of an eGo-object that still refers to the (outdated) ego.io interface here:

eGo/ego/tools/io.py

Lines 96 to 102 in 20634a3

	try:
	conn = db.connection(section=self.json_file["eTraGo"]["db"])
	Session = sessionmaker(bind=conn)
	self.session = Session()
	logger.info("Connected to Database")
	except: # noqa: E722
	logger.error("Failed connection to Database", exc_info=True)

The whole database-connection-settings is sth. we need to adjust and only give the connection parameters once for eGo, eTraGo, and eDisGo.