Adding webserver mode to the system console. Automatic enabling of gzip on existing servers (#3458)

config/config.json

@@ -23,7 +23,7 @@
         "SessionCacheInMinutes": 10,
         "WebsocketSecurePort": 443,
         "WebsocketPort": 80,
-        "WebserverMode": "regular",
+        "WebserverMode": "gzip",
         "EnableCustomEmoji": false,
         "RestrictCustomEmojiCreation": "all"
     },
@@ -188,4 +188,4 @@
         "LocaleAttribute": "",
         "LoginButtonText": "With SAML"
     }
-}
+}