Change paste settings and add copyright headers

- There's now a notice reminding people to change the base URL if they
  had a custom base URL and change the paste type (that was something I
  personally had problems with when I was testing, so a reminder was
  helpful for me).

- Broke down some of the long lines on APIPage.cpp to be more readable.

- Added copyright headers where they were missing.

- Changed the paste service display names to the names they are more
  commonly known by.

- Changed the default hastebin base URL to https://hst.sh due to the
  acquisition of https://hastebin.com by Toptal.

launcher/Application.cpp

@@ -2,6 +2,7 @@
 /*
  *  PolyMC - Minecraft Launcher
  *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *  Copyright (C) 2022 Lenny McLennington <lenny@sneed.church>
  *
  *  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
@@ -672,7 +673,7 @@ Application::Application(int &argc, char **argv) : QApplication(argc, argv)
 
         m_settings->registerSetting("UpdateDialogGeometry", "");
 
-        // This code feels so stupid is there a less stupid way of doing this?
+        // HACK: This code feels so stupid is there a less stupid way of doing this?
         {
             m_settings->registerSetting("PastebinURL", "");
             QString pastebinURL = m_settings->get("PastebinURL").toString();
@@ -694,7 +695,7 @@ Application::Application(int &argc, char **argv) : QApplication(argc, argv)
             }
 
             bool ok;
-            unsigned int pasteType = m_settings->get("PastebinType").toUInt(&ok);
+            int pasteType = m_settings->get("PastebinType").toInt(&ok);
             // If PastebinType is invalid then reset the related settings.
             if (!ok || !(PasteUpload::PasteType::First <= pasteType && pasteType <= PasteUpload::PasteType::Last))
             {