Create new error message for unsupported TOSCA types

Heat-Translator should provide a more user friendly error message for all the TOSCA types it does not or can not support translation. For example, if a type 'tosca.nodes.Container.Application' is not yet supported for translation or there is no way to map it to HOT it should thrown an error accordingly instead of 'invalidTypeError'.
At high level, the work includes,
1. Create a list or a text file with list of TOSCA types or a particular TOSCA entities that are not supported for translation at a given point of time. Create a similar list for TOSCA types or a particular TOSCA entity that can not be translated in to HOT.
2. Create a new error type, something like, UnsupportedTypeError
3. When attempt to translate types provided in a TOSCA service template, verify that they are valid types using TOSCA definition file of TOSCA Parser. If it's valid, check if they are unsupported or can not be translated. If so, raise UnsupportedTypeError with a specific message like "UnsupportedTypeError: Type 'xyz' is valid but not supported at this time" or "UnsupportedTypeError: Type 'xyz' is valid but can not be supported to translate to HOT because it can not be mapped into HOT"
NOTE: In future, if we decide to 'pass' such an unsupported type without translation, instead of error, create UnsupportedTypeWarning and continue translation (this can be dangerous as it can produce a HOT template that is broken and can not be deployed, but if such a need come up and user is comfortable to choose such an option we will treat this as a separate work item and work on it)

For a somewhat similar work in tosca-parser, refer to the, https://blueprints.launchpad.net/tosca-parser/+spec/unsupported-type-validation