@karlitschek This apps should have a function to "expose" their existence (e.g. a call to a function called "OC_API::Expose()")

> This is a password protected feature which is only available to users with accounts who can see the apps in the web-interface anyways. 

Not every app is shown in the web-interface, why should my users know if I have for example `user_webdavauth` installed? - This is just an uneeded information exposure.