Bug 480875

I know there has been a lot of discussion on single click versus double click and double click was chosen because every distro defaults to it. I do agree with this when using mouse input devices. But for touch, it does not make a lot of sense for the following reasons:

- Opening recently used files in for example Okular or Kate is impossible with touch (see https://bugs.kde.org/show_bug.cgi?id=480375 for details)
- You need many tries to open a folder (not from the side bar) in the file picker because there is no consistently working way to do it via touch
- Dolphin handles this by already automatically switching to single tap when the tap is not a mouse click but a touch tap. So switching to single click entirely in tablet mode would only make this more consistent

An alternative to autoswitching to single click would of curse be adressing the first two issues individually. But this would make it quite likely that many more issues like these would pop up over time which would need to be adressed one by one. That is why I chose to primarily propose autoswitching to single click in tablet mode. Maybe there is also another even more elegant solution, but I don't know how this works internally well enough to judge this properly.