Add fish wrapper and make it my default shell

wrappers/fish/default.nix

@@ -0,0 +1,15 @@
+{lib, pkgs, ...}: {
+  # TODO: Fix once https://github.com/viperML/wrapper-manager/issues/14 is resolved
+  wrappers.fish = {
+    basePackage = pkgs.runCommandNoCC "fish-binary" {} ''
+      install -D -m555 ${lib.getExe pkgs.fish} "$out/bin/fish"
+    '';
+
+    prependFlags = [
+      "-C"
+      "source ${./config.fish}"
+    ];
+
+    pathAdd = with pkgs; [bat eza];
+  };
+}