Delete mechanism for deployments utilizing Foreman action button.

Destroy method

Success alert

Engine fix for extensions

Hostgroup child delete.

Fix delete cascade
Merge pull request #30 from knowncitizen/delete_deployment_ui

Delete deployment UI
Update Deployment::Deploy action to use new model
Remove nested load_paths to avoid problems

moving concerns to its namespace
#destroy is always true

or it raises on error
Fix creation of nested Hostgroups
Add check to remove the nest method when upgraded to 1.5
Fix hostgroup lookup
Merge pull request #32 from pitr-ch/orchestration

Update Deployment::Deploy action to use new model, other minor improvements