DevTools: move UI components to target observers in preparation to early UI initialization.

Source/devtools/front_end/elements/module.json

 {
     "extensions": [
         {
             "type": "@WebInspector.Panel",
             "name": "elements",
             "title": "Elements",
             "order": 0,
             "className": "WebInspector.ElementsPanel"
         },
         {
             "type": "@WebInspector.ContextMenu.Provider",
             "contextTypes": ["WebInspector.RemoteObject", "WebInspector.DOMNode"],
             "className": "WebInspector.ElementsPanel.ContextMenuProvider"
         },
         {
-            "type": "drawer-view",
-            "name": "rendering",
-            "title": "Rendering",
-            "order": "11",
-            "className": "WebInspector.RenderingOptionsView"
-        },
-        {
             "type": "@WebInspector.Renderer",
             "contextTypes": ["WebInspector.DOMNode"],
             "className": "WebInspector.ElementsTreeOutline.Renderer"
         },
         {
             "type": "@WebInspector.Revealer",
             "contextTypes": ["WebInspector.DOMNode"],
             "className": "WebInspector.ElementsPanel.DOMNodeRevealer"
         },
         {
@@ skipping 38 matching lines @@
         {
             "type": "ui-setting",
             "section": "Elements",
             "title": "Show rulers",
             "settingName": "showMetricsRulers",
             "settingType": "checkbox"
         }
     ],
     "scripts": [ "ElementsPanel.js" ]
 }