plugins: set lazy to true for some md plugins

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

lua/custom/plugins/rainbow-csv.lua

@@ -3,6 +3,7 @@
 return {
     'cameron-wags/rainbow_csv.nvim',
     config = true,
+    lazy = true,
     ft = {
         'csv',
         'tsv',

lua/custom/plugins/vim-markdown.lua

@@ -12,6 +12,7 @@ vim.cmd([[ let g:vim_markdown_frontmatter = 1 ]])
 return {
   {
     "preservim/vim-markdown",
+    lazy = true,
     ft = {
       'markdown'
     }