Move the time configuration from controller to model

Conflicts:
	plugins/time/app/controllers/time_controller.rb
	plugins/time/app/views/time/index.html.erb
Add authorization for Service
Finalize the time config in model and controller
Add a real working ntp server
Add info about config for user

Conflicts:
	plugins/time/app/views/time/index.html.erb
Do not need permission for ntp sync
Update tests
Avoid nil if service returns it
Update restdoc
time - updated changes