Make Queue editable

[AustrianLinuxMemer]

Problem

The problem I see with the queue as it stands now is that there is no way to edit the queue after files have been added. It is possible to add files to the queue but there is no way to move items in the queue or to clear the queue without closing the program

Proposal

I would propose:

• To add a way to move the items in the queue per drag-and-drop
• To add a way to be able to remove items from the queue (either through some button on the item itself on the item or through a context menu)
• To add a way to be able to empty the queue without closing the application

Prior Art (Optional)

[danirabbit]

This should probably be split into three separate issues or at least done in three separate pull requests:

• One for adding a context menu to items
• One for implementing drag-n-drop rearrange
• One for adding a method to clear the whole queue