Add newer option names to storybook__addon-options

Following https://github.com/storybooks/storybook/pull/1692/files

```
showLeftPanel    -> showStoriesPanel
showDownPanel    -> showAddonPanel
downPanelInRight -> addonPanelInRight
```

types/storybook__addon-options/index.d.ts

@@ -2,6 +2,7 @@
 // Project: https://github.com/storybooks/storybook
 // Definitions by: Joscha Feth <https://github.com/joscha>
 //                 Simon Helle Nielsen <https://github.com/simonhn>
+//                 A.MacLeay <https://github.com/amacleay>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 2.3
 
@@ -9,10 +10,13 @@ export interface Options {
     name?: string;
     url?: string;
     goFullScreen?: boolean;
-    showLeftPanel?: boolean;
-    showDownPanel?: boolean;
+    showLeftPanel?: boolean; // deprecated, use showStoriesPanel
+    showStoriesPanel?: boolean;
+    showDownPanel?: boolean; // deprecated; use showAddonPanel
+    showAddonPanel?: boolean;
     showSearchBox?: boolean;
-    downPanelInRight?: boolean;
+    downPanelInRight?: boolean; // deprecated; use addonPanelInRight
+    addonPanelInRight?: boolean;
     sortStoriesByKind?: boolean;
     hierarchySeparator?: RegExp | string;
     hierarchyRootSeparator?: RegExp | string;

types/storybook__addon-options/storybook__addon-options-tests.ts

@@ -4,6 +4,19 @@ setOptions({
   name: 'My Storybook',
   url: 'https://example.com',
   goFullScreen: false,
+  showStoriesPanel: false,
+  showAddonPanel: false,
+  showSearchBox: false,
+  addonPanelInRight: false,
+  sortStoriesByKind: false,
+  hierarchySeparator: /\//,
+  hierarchyRootSeparator: /\|/
+});
+
+setOptions({
+  name: 'My Storybook - deprecated options',
+  url: 'https://example.com',
+  goFullScreen: false,
   showLeftPanel: false,
   showDownPanel: false,
   showSearchBox: false,