[Screenshotting] Organize dev docs for screenshotting/chromium (#198100)

* Remove duplicated “File service” entry from nav
* Move Screenshotting to main Tutorials section in nav 
* Add “Updating Puppeteer and Chromium” to nav as a sub-item of
screenshotting
* Move files for Screenshotting/Chromium out of the SharedUX space to
`dev_docs/tutorials/screenshotting`

Author: tsullivan

dev_docs/nav-kibana-dev.docnav.json

@@ -183,8 +183,13 @@
           "label": "data.search"
         },
         {
-          "id": "kibDevTutorialFileService",
-          "label": "File service"
+          "id": "kibDevTutorialScreenshotting",
+          "label": "Screenshotting",
+          "items": [
+            {
+              "id": "kibDevDocsUpdatingPuppeteerAndChromium"
+            }
+          ]
         },
         {
           "id": "kibDevTutorialDataViews"
@@ -266,10 +271,6 @@
             }
           ]
         },
-        {
-          "id": "kibDevTutorialScreenshotting",
-          "label": "Screenshotting"
-        },
         {
           "id": "kibDevTutorialAdvancedSettings",
           "label": "Advanced Settings"

dev_docs/shared_ux/shared_ux_landing.mdx

@@ -46,16 +46,6 @@ layout: landing
       pageId: 'kibContentManagement',
       description: 'Learn about the content management system in Kibana',
     },
-    {
-      pageId: 'kibDevTutorialScreenshotting',
-      title: 'Reporting / Screenshotting',
-      description: 'Learn how to integrate your plugin with reporting',
-    },
-    {
-      pageId: 'kibDevDocsUpdatingPuppeteerAndChromium',
-      title: 'Reporting / Updating Puppeteer and Chromium',
-      description: 'Learn how to update the Puppeteer node module and build headless Chromium',
-    },
     {
       pageId: 'kibDevTutorialAdvancedSettings',
       title: 'Advanced Settings (uiSettings)',