frontend: editor: improve View layout modification interface

[ES-Alexander]

Regular Widgets

• click to select a widget (there should always be one selected)
  • click the widget name in the dropdown at the top of the right sidebar to select a different widget, if visual selecting is hard
    • should open a scrollable list like the current "Widgets in View" list in the left sidebar
  • change the variant in the second from top dropdown in the right sidebar
    • switching from a regular to mini variant should choose a mini-widget container to put it into (maybe the closest one, or maybe consistently in the bottom middle), and switching from mini to regular should place the widget in the middle of the standard area
  • drag to move (or use the "Move" tab in the right sidebar, with either the onscreen joystick or the X/Y value entries)
    • there are also buttons and an entry for shifting the widget depth, either incrementally or jumping to the top/bottom
  • pull corners/sides to resize (or use the "Resize" tab in the right sidebar)
    • there is also a button to make the widget fill the screen (or return a fullscreen widget to resizable)
  • click again to configure (or use the "Edit" button in the right sidebar)
  • click the delete button to remove

Mini Widgets

• largely similar to the regular widget case, but
  • there's no resizing, and
  • movements are instead in terms of position/order within the current container, and changing which container the widget is in

[rafaellehmkuhl]

Amazing work

This should be our goal