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/ui/pages/global/APIPage.h

@@ -3,6 +3,7 @@
  *  PolyMC - Minecraft Launcher
  *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *  Copyright (c) 2022 Jamie Mansfield <jmansfield@cadixdev.org>
+ *  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
@@ -73,6 +74,9 @@ public:
     void retranslate() override;
 
 private:
+    int baseURLPasteType;
+    void resetBaseURLNote();
+    void updateBaseURLNote(int index);
     void updateBaseURLPlaceholder(int index);
     void loadSettings();
     void applySettings();