SSDM-6476: removed data_set_ prefix from data set settings

src/python/OBis/integration_tests/integration_tests.py

src/python/OBis/obis/dm/commands/openbis_command.py

src/python/OBis/obis/dm/commands/openbis_sync.py

src/python/OBis/obis/dm/config.py

src/python/OBis/obis/dm/data_mgmt.py

src/python/OBis/obis/dm/data_mgmt_test.py

src/python/OBis/obis/scripts/cli.py