Enhance SoftwareComponent property validation

This patch enhances the property validation for
OS::Heat::SoftwareComponent beyond what is done with property schema
validation. This allows for reporting additional validation errors
to users.

Implements: partial-blueprint action-aware-sw-config

Change-Id: I512c74341d9271bc07f78149d45d662484241ada
Merge "Enhance SoftwareComponent property validation"