migrated to lazy.nvim, cleanup and fixes

lua/defs.lua

@@ -1,7 +1,7 @@
 return {
 	template_dir = '~/templates',
-	external_term = 'kgx',
-	external_filemgr = 'nautilus',
-	external_pdfviewer = 'evince',
+	external_term = 'xfce4-terminal',
+	external_filemgr = 'thunar',
+	external_pdfviewer = 'atril',
 	lsp_path = vim.env.HOME .. '/.local/share/lsp_servers'
 }