Added docs for open source Navigation Plugin

Summary:
Added docs for the Navigation Plugin.

I've added instructions on how to use the plugin with vanilla Android, or how to integrate it with a third party solution.

Reviewed By: danielbuechele

Differential Revision: D16856614

fbshipit-source-id: e99cb94318820bd926f50bd4ba205fb11396a9d8

website/i18n/en.json

@@ -81,6 +81,9 @@
       "features/logs-plugin": {
         "title": "Logs"
       },
+      "features/navigation-plugin": {
+        "title": "Navigation"
+      },
       "features/network-plugin": {
         "title": "Network"
       },
@@ -116,6 +119,10 @@
         "title": "LeakCanary Setup",
         "sidebar_label": "LeakCanary"
       },
+      "setup/navigation-plugin": {
+        "title": "Navigation Plugin Setup",
+        "sidebar_label": "Navigation"
+      },
       "setup/network-plugin": {
         "title": "Network Setup",
         "sidebar_label": "Network"

website/sidebars.json

@@ -4,6 +4,7 @@
       "features/index",
       "features/logs-plugin",
       "features/layout-plugin",
+      "features/navigation-plugin",
       "features/network-plugin",
       "features/databases-plugin",
       "features/images-plugin",
@@ -15,12 +16,10 @@
     ]
   },
   "setup": {
-    "Using Flipper": [
-      "getting-started",
-      "troubleshooting"
-    ],
+    "Using Flipper": ["getting-started", "troubleshooting"],
     "Plugin Setup": [
       "setup/layout-plugin",
+      "setup/navigation-plugin",
       "setup/network-plugin",
       "setup/databases-plugin",
       "setup/images-plugin",
@@ -58,9 +57,6 @@
       "extending/establishing-a-connection",
       "extending/supporting-layout"
     ],
-    "Internals": [
-      "extending/arch",
-      "extending/layout-inspector"
-    ]
+    "Internals": ["extending/arch", "extending/layout-inspector"]
   }
 }