Allow Applications to create dedicated Tours

An Application should define a dependency to the Tour Application and be able to launch a Tour only to a particular Space or action performed.

We could have a Tour applications homepage that lists all the tour that exists on a particular wiki, but Tours can have categories. For example we could define an "Applications" category that could be used by Applications, and that would help the users filter these types of tours in the Homepage's livetable. (Offtopic: other categories for example could be tour dedicated to a particular Flavor, or a particular type of user [developer, admin] but about standard features = we could have categories and difficulties)