Add tasks in advance and optimize tasks handling

[tobka777]

As a user, I want to create my tasks in advance so that I can quickly switch tasks in the workflow.

• Best is to add a button in the upper area of the app, e.g. next to Rename with the name Add.
  With a click on the button, it will be add the Name (and Clarity Account, Comment) to tasklist (see in Dropdown).

• Context Menu should only show the tasks which are in the tasklist in the Dropdown and no duplicates.

• If the user click Other... in the Context Menu and choose a task from the list, the clarity account + comment will be set too. (Bug only if slice is undefined/ no clarity task before)