Remove dead fonts.nix stub

home/fonts.nix only set fonts.fontconfig.enable = true, which home-manager
enables automatically when font packages are declared. Delete the file and
remove its imports from both host home.nix files.

hosts/nikita-nixos/home.nix

@@ -3,7 +3,6 @@
 {
   imports = [
     ../../home/zsh.nix
-    ../../home/fonts.nix
     ../../home/yazi.nix
     ../../home/symlinks.nix
     ../../home/packages-base.nix