No event notifications when Resuming/Suspending indexing of resources

Indexing is a background process that the user shouldn't be aware about.
We should just work, and not annoy the user about stuff like this.

Added a config option in nepomukstrigirc just in case anyone wants it.
Add ShowSuspendResumeEvents = true in [General]

BUG: 196261
REVIEW: 105271