refactor: delete old Ansible configuration

- Remove the Ansible files.
- Move the Nix files to the root level of the repository.

Refs: #39

home-manager/apollo.nix

@@ -0,0 +1,40 @@
+{ config, lib, pkgs, ... }:
+
+{
+  imports = [
+    ./modules/common.nix
+    ./modules/git.nix
+    ./modules/home-manager.nix
+    ./modules/tmux.nix
+    ./modules/zsh.nix
+  ];
+
+  home.stateVersion = "22.05";
+
+  home.username = "opdavies";
+  home.homeDirectory = "/home/opdavies";
+
+  programs.alacritty = {
+    enable = true;
+
+    settings = {
+      window.padding = {
+        x = 15;
+        y = 15;
+      };
+
+      font = {
+        size = 12.0;
+
+        normal.family = "JetBrainsMono Nerd Font";
+
+        offset.y = 12;
+        glyph_offset.y = 6;
+      };
+
+      shell = {
+        program = "zsh";
+      };
+    };
+  };
+}