USABILITY: Enable the Teiid translator to derive what push-down functions are supported by means other than the user having to extend the translator class

In order for the user to enable a push-down function to a specific data source, they must extend the Translator class, create a new jar and deploy to the server. This is big usability flaw (and a headache to clients) in just providing the function signature that is supported to be pushed down to the source. There are easier ways for the user to provide this information without having to touch java.