Unify widget state image suffixes (disabled, pressed, hover, focus)

- Add a property for arrows image collection (in drop-downs, scrollbars
and production tabs)
- Add a property for separators image collection (in drop-downs)
- Add hover and disable states to the drop-down separator
- Unify button, textfield and checkbox state suffixes

mods/d2k/chrome/ingame-player.yaml

@@ -616,8 +616,8 @@ Container@PLAYER_WIDGETS:
 								Image@ICON:
 									X: 5
 									Y: 5
-									ImageCollection: scrollbar
-									ImageName: up_arrow
+									ImageCollection: scrollpanel-decorations
+									ImageName: up
 						Button@SCROLL_DOWN_BUTTON:
 							Y: 248
 							Width: 25
@@ -630,5 +630,5 @@ Container@PLAYER_WIDGETS:
 								Image@ICON:
 									X: 5
 									Y: 5
-									ImageCollection: scrollbar
-									ImageName: down_arrow
+									ImageCollection: scrollpanel-decorations
+									ImageName: down