treewide: Change URLs to HTTPS

Lots of URLs were HTTP redirect to HTTPS. Changed those and checked them
if there's actual content. Inspired by
https://github.com/NixOS/nixpkgs/issues/60004

pkgs/development/libraries/libmikmod/default.nix

@@ -20,7 +20,7 @@ in stdenv.mkDerivation rec {
 
   meta = with stdenv.lib; {
     description = "A library for playing tracker music module files";
-    homepage    = http://mikmod.shlomifish.org/;
+    homepage    = https://mikmod.shlomifish.org/;
     license     = licenses.lgpl2Plus;
     maintainers = with maintainers; [ astsmtl lovek323 ];
     platforms   = platforms.unix;