Initial plugin setup (#1)

This adds a basic layer of plugins. But more language and workflow specific plugins are to follow possibly.

lua/custom/plugins/filesystem.lua

@@ -0,0 +1,30 @@
+-- File navigation using neo-tree
+return {
+  'nvim-neo-tree/neo-tree.nvim',
+  branch = 'v3.x',
+  dependencies = {
+    'nvim-lua/plenary.nvim',
+    'nvim-tree/nvim-web-devicons', -- not strictly required, but recommended
+    'MunifTanjim/nui.nvim',
+    -- {"3rd/image.nvim", opts = {}}, -- Optional image support in preview window: See `# Preview Mode` for more information
+  },
+  lazy = false, -- neo-tree will lazily load itself
+  ---@module "neo-tree"
+  ---@type neotree.Config?
+  config = function()
+    require('neo-tree').setup {
+      event_handlers = {
+        {
+          event = 'file_open_requested',
+          handler = function()
+            -- auto close
+            vim.cmd 'Neotree close'
+          end,
+        },
+      },
+    }
+  end,
+  opts = {
+    -- fill any relevant options here
+  },
+}