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/python-modules/nxt-python/default.nix

@@ -14,7 +14,7 @@ buildPythonPackage rec {
   disabled = isPy3k;
 
   src = fetchgit {
-    url = "http://github.com/Eelviny/nxt-python";
+    url = "https://github.com/Eelviny/nxt-python";
     rev = "479e20b7491b28567035f4cee294c4a2af629297";
     sha256 = "0mcsajhgm2wy4iy2lhmyi3xibgmbixbchanzmlhsxk6qyjccn9r9";
     branchName= "pyusb";