add postgres db connector with ssh tunneling and configuration reader

The main is not necessary but nice for single use. can run with python retrieve_db_connection.py -s postgresql-ldv when connecting to the actual ldvadmin db or python retrieve_db_connection.py -s postgresql-local for your local docker container

the connector returns the connection but also the server (if any) and have to be stopped after doing smth with it

requested review from @goei

assigned to @lautenbach

added 1 commit

• 5e10559c - MR comments; exception handling for unknown files, change ini format to cfg format

Compare with previous version

resolved all threads

enabled an automatic merge when the pipeline for 5e10559c succeeds

mentioned in commit f024b925

merged

mentioned in commit fd83fd34