Enable support for software component

The group property indicates whether it is softwarecomponent or plain
softwareconfig.
If it is softwarecomponent, recognizes 'configs' section in metadata,
and choose a proper config to invoke depending on the 'deploy_action'
value.

Partially implements: blueprint action-aware-sw-config

Change-Id: I503032ed09fb5448da225c53c690543fa30d957f