CLI Validator for TOSCA templates

Create a stand alone validation that can invoke from command line with a yaml template or CSAR. The validator will vaildate main template and referenced templates given in imports, assuming their location/path is reachable.
The validator should potentially validate syntax for TOSCA keywords, correctness of provided TOSCA types in template, correctness of various section names in template etc.
The existing validation code may need to move on to a new validation module which can provide various validation functions.

 The --validate key word will be added in Heat-Translator that will take a template or CSAR as an input value. This will be done under a separate blueprint created in Heat-Translator and facilitate user to only run validation vs translation.
This should run a TOSCA validator against the wordpress.yaml (for example) with an output something like:
"The wordpress.yaml has successfully passed validation" (when it passes validation)
OR
"The wordpress.yaml has failed validation with following errors.." (Which will list errors with detail like particular line numbers in template, what is the solution etc.)