Encode parameters in `OC.generateUrl` by itself

This function is often used in a wrong and potential dangerous way... Thus we should escape the URL per default and offer developers to disable the automatic escaping via an option parameter if they really want that behaviour.

Might break some things, however, those things are then easy to fix and we really have a ton of bugs caused by this...

Fixes https://github.com/owncloud/core/issues/14228