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/proj/default.nix

@@ -12,7 +12,7 @@ stdenv.mkDerivation {
 
   meta = with stdenv.lib; {
     description = "Cartographic Projections Library";
-    homepage = http://trac.osgeo.org/proj/;
+    homepage = https://proj4.org;
     license = licenses.mit;
     platforms = platforms.linux ++ platforms.darwin;
     maintainers = with maintainers; [ vbgl ];