plugins: remove the ZenMode plugin

- Removes the ZenMode plugin as I should have done long ago.
- Lazy loads the Rainbow CSV plugin.

Co-Authored-by: iGor milhit <igor@milhit.ch>

lua/custom/plugins/rainbow-csv.lua

@@ -2,6 +2,7 @@
 
 return {
     'cameron-wags/rainbow_csv.nvim',
+    lazy = true,
     config = true,
     ft = {
         'csv',

lua/custom/plugins/zen-mode.lua

@@ -1,39 +0,0 @@
---  Zen mode with twilight.
---    Improves the edition experience with distraction free feature.
-
-return {
-  "folke/zen-mode.nvim",
-  ft = {
-    "markdown",
-    "pandoc"
-  },
-  -- Twilight allows to dim text outside of the cursor line.
-  dependencies = {
-    "folke/twilight.nvim",
-    opts = {
-      -- Set the context to null in order to avoid highlighting to much
-      -- paragraphs in markdown.
-      context = 0,
-    },
-  },
-  opts = {
-    window = {
-      -- Set the window width (85 columns) and height (80%).
-      width = 85,
-      height = .8,
-      options = {
-        -- Disable line numbering, signcolumn and colorcolumn.
-        number = false,
-        signcolumn = "no",
-      },
-    },
-    plugins = {
-      options = {
-        enabled = true,
-        ruler = false,
-        showcmd = false,
-      },
-      gitsigns = { enabled = false },
-    },
-  },
-}