Improve database .cli scripts for better user experience

Currently the .cli scripts are very simple and don't handle exceptions well.

For example, when user first runs "mysql" cli script, then remove datasource and then wants to add the datasource again by running the "mysql" cli script, he gets duplicate resource error. A skilled EAP user will probably know how to fix it and where the problem was, but it would still be better to make those scripts more robust (for example in case of error when registering a driver, let the user know that the driver could not be registered and that it is probably because he already has the driver installed also providing required steps to remove the driver).

In case we won't be able to get this fixed, I suggest that we write about this possible problem to KSC, so there will be the solution available.