See commit f33eb08a for details

TODO: reimplement defaults to be taken from the Drivers.xcu, not from
ODatabaseModelImpl::getDefaultDataSourceSettings.

TODO: always write settings, even if they are equal to defaults (unless
they are schema defaults) - that will allow to change a default, and not
break existing configurations.

Change-Id: Ic0fa9a03bf801aeca3e6373eb7019f5ad7e8eb46
Reviewed-on: https://gerrit.libreoffice.org/69076
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>