Add ability to set conditions (by language and content-type) on templates

We have a use-case where the client needs to make templates available only to certain content-types and only in the user's current language. For example if you have a service content-type it might be nice to have two templates available: service simple and service complex. And, for the Government of Canada the template must be in the user's current language so it would be good to not have all the translations of the templates as well.

Ideally this module could use the core Conditions system, but this might be quite a bit of work.