Initial add basic groovy plugin support
Initial notification plugins for #360
Consolidate and improve DescriableService impl
Use annotation metadata for plugin title/description
instance only property resolver for plugins
Handle potential null content for notification
getType added to PropertyBuilder
Add groovy DSL support for plugin scripts
Remove unneeded interface methods for NotificationPlugin
Add validation to notification plugins
Add codec tests for notification plugins
Update tests for controllers and services
Improve gui for notifications
Fix builder delegates
Improve execution context data passed to notify plugins
Fix issue modifying notifications
Fix create job notifications
Enable onstart notification
Fix xml/yaml format
Test fixes