treewide: update homepages to https where available

Based on "problems" from repology:

https://repology.org/repository/nix_unstable/problems

Mostly simple changes to reflect redirects.

pkgs/development/libraries/libestr/default.nix

@@ -9,7 +9,7 @@ stdenv.mkDerivation rec {
   };
 
   meta = with stdenv.lib; {
-    homepage = http://libestr.adiscon.com/;
+    homepage = https://libestr.adiscon.com/;
     description = "Some essentials for string handling";
     license = licenses.lgpl21;
     platforms = platforms.all;