Add a toolbar to the application

[fbergmann]

So ideally, we would have a toolbar with actions from the main menu. Currently some things are odd with it:

• when the actions are initially created, they should have been created with icons / shortcuts

since that didn't happen, the toolbar right now has really long names.

I suggest, that we separate creating actions from adding them to menu / toolbars / controllers as discussed earlier today.

[fbergmann]

I'll add the icons for the two elements I'm using and then merge, then it will look better