[Chore] Remove dependency between hackage-search and hackage-download

Problem: The services are designed to be independent and only share
the common data directory.

Solution: Remove 'Requires' and 'After' dependecies on
'hackage-download' for 'hackage-search' service

Author: rvem

service.nix

@@ -65,7 +65,7 @@ in {
       hackage-search = rec {
         wantedBy = [ "multi-user.target" ];
 
-        requires = [ "hackage-download.service" ];
+        requires = [ "network-online.target" ];
         after = requires;
 
         path = with pkgs; [ ripgrep cfg.package ];