hosts: split zsh into a module

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

hosts/modules/zsh/default.nix

@@ -0,0 +1,13 @@
+{ ... }:
+{
+  programs.zsh = {
+    enable = true;
+    histSize = 30000;
+    enableBashCompletion = true;
+    enableCompletion = true;
+    autosuggestions = {
+      enable = true;
+      highlightStyle = "fg=yellow,bold";
+    };
+  };
+}