feat: use natural sort order by default (#328)

* Sort entries with natural sorting

* refactor: move natural ordering logic and add config option

---------

Co-authored-by: Steven Arcangeli <stevearc@stevearc.com>

lua/oil/config.lua

@@ -90,6 +90,9 @@ local default_config = {
     is_always_hidden = function(name, bufnr)
       return false
     end,
+    -- Sort file names in a more intuitive order for humans. Is less performant,
+    -- so you may want to set to false if you work with large directories.
+    natural_order = true,
     sort = {
       -- sort order can be "asc" or "desc"
       -- see :help oil-columns to see which columns are sortable