Restrict create_stack callback at first time only
Remove already unnecess aryarguments from call of CloudConductor::Client
Change check logic to notice a completion of stack
Add Serf::Client to request serf
Use Serf::Client to check running status of serf on frontend server
Call configure event when stack has created
Add template_parameters column to divide usage between template variable and serf payload

Conflicts:
	spec/src/models/system_spec.rb
	src/models/system.rb
Restore original callback that contains if condition
Change payload structure to new format that contains parameters key
Refactoring: Remove redundant yield from stack_observer logic
Merge branch 'feature/stack-observer' into develop