Changes: Simplified form controls

[bastianallgeier]

Description

Summary of changes

• The form controls component is now stored in the Forms folder. There's no reason to have a subfolder as long as we don't have any other control components
• The form controls go back to the original form button design, but with Discard instead of Revert
  
• The component only has two states is-unsaved & is-locked
• Additional information about the editor and modification time can be passed as additional arguments for the new lock dropdown
  

Todos

• We might want to change the button color back to green or something else in a later step.
• We also might want to change the "Save" icon and wording. But it's unclear at this point what it should be.