Restructure Darwin configuration

So far, this is just based on mightymac. The other devices will be
updated soon.

modules/hosts/common/files/nvim/lua/disabled/barbar.lua

@@ -0,0 +1,14 @@
+return {'romgrk/barbar.nvim',
+  dependencies = {
+    'lewis6991/gitsigns.nvim', -- OPTIONAL: for git status
+    'nvim-tree/nvim-web-devicons', -- OPTIONAL: for file icons
+  },
+  init = function() vim.g.barbar_auto_setup = false end,
+  opts = {
+    -- lazy.nvim will automatically call setup for you. put your options here, anything missing will use the default:
+    -- animation = true,
+    -- insert_at_start = true,
+    -- …etc.
+  },
+}
+