Allow custom Modrinth API token

Signed-off-by: TheKodeToad <TheKodeToad@proton.me>

launcher/Application.h

@@ -3,6 +3,7 @@
  *  Prism Launcher - Minecraft Launcher
  *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *  Copyright (C) 2022 Tayou <tayou@gmx.net>
+ *  Copyright (C) 2023 TheKodeToad <TheKodeToad@proton.me>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -177,6 +178,7 @@ public:
 
     QString getMSAClientID();
     QString getFlameAPIKey();
+    QString getModrinthAPIToken();
     QString getUserAgent();
     QString getUserAgentUncached();