Several configurable nice-to-haves

Hi colleagues,

I'm using your CQ Groovy console in several projects and it helps me a lot during urgent maintenance/migration tasks, so thank you for sharing it with others! 

What I'd like to contribute now is a couple of nice-to-have configurable features which might be useful during work.
This pull request contains:
- Groovy Console Configuration service which allows to enable/disable certain operations on a particular CQ landscape (available at http://localhost:4502/system/console/configMgr);
- Email notifications which are sent to specified recipient(s) after script is run. Useful when you need to control/review executions more thoroughly;
- Saving output results as files (nt:file) in CRX under specified folder. File path contains date/time of execution, so it's pretty easy to understand when and what was executed.

If you find it useful, feel free to merge.

Regards,
Vladimir