Green plus button in header that opens a drop down menu with the following options:

* Work package
* Opens work package form. The current project is pre-selected.
* Project Begin of the insertion
* When inEnd of the insertion Begin of the deletion (To be clarified: Creates a newEnd of the deletion project Begin of the insertioncontext, selectsEnd of the insertion Begin of the deletion withEnd of the deletion the current project Begin of the deletion setEnd of the deletion as Begin of the insertionparentEnd of the insertion Begin of the deletion parent)End of the deletion
* Add user, if you have
* the global permission to create/invite users OR
* if you are in a project AND you have the right to add members or placeholder users to that project

Affects:

* Header layout. In order to avoid overlapping elements we need to take space away from other header elements. Maybe from the search input? Or we could move the "Help" menu somewhere else?