feat(nix): nix and back again

I tried Nix, but it had too many downsides so I removed it.

1. Didn't like that all files are immutable and simple config changes
need a complete rebuild.
2. Setting up a new Mac didn't work as smoothly as promised. Not worth
the effort.
3. It sucked a lot to always have to type in the password twice on each
darwin-rebuild
4. It solves problems I never had.

.config/nvim/lua/plugins/gh.lua

@@ -0,0 +1,28 @@
+-- A fully featured GitHub integration for performing code reviews
+-- https://github.com/ldelossa/gh.nvim
+return {
+  "ldelossa/gh.nvim",
+  dependencies = { "ldelossa/litee.nvim" },
+  config = function()
+    require("litee.lib").setup()
+    require("litee.gh").setup({
+      jump_mode = "invoking",
+      map_resize_keys = false,
+      disable_keymaps = false,
+      icon_set = "default",
+      icon_set_custom = nil,
+      git_buffer_completion = true,
+      keymaps = {
+        open = "<CR>",
+        expand = "zo",
+        collapse = "zc",
+        goto_issue = "gd",
+        details = "d",
+        submit_comment = "<C-s>",
+        actions = "<C-a>",
+        resolve_thread = "<C-r>",
+        goto_web = "gx",
+      },
+    })
+  end,
+}