WIP Adding scheduler redirection layer to core

As the scheduler now comes from a plugin:
* Scheduler is not available before NexusStartedEvt (nxApp fixed)
* provided indirection layer, that will use nothing, legacy or quartz
* smaller fix for legacy restlet1x resource to support "no scheduler" state
WIP Quartz backing legacy scheduler

Changes:
This is a working version of quartz backed NexusScheduler.

Smaller bugfixes made for KZ JobDao, and also smaller relocations
made in code for better structuring.