Disable Gfycat by default during Beta and move default keys to server (#9027)

* Update default.json

* Update diagnostics.go

* Added default Gfycat API credentials to server

* Fixed default Gfycat credentials

config/default.json

@@ -44,9 +44,9 @@
         "WebserverMode": "gzip",
         "EnableCustomEmoji": false,
         "EnableEmojiPicker": true,
-        "EnableGifPicker": true,
-        "GfycatApiKey": "",
-        "GfycatApiSecret": "",
+        "EnableGifPicker": false,
+        "GfycatApiKey": "2_KtH_W5",
+        "GfycatApiSecret": "3wLVZPiswc3DnaiaFoLkDvB4X0IV6CpMkj4tf2inJRsBY6-FnkT08zGmppWFgeof",
         "RestrictCustomEmojiCreation": "all",
         "RestrictPostDelete": "all",
         "AllowEditPost": "always",