[RTL UI] Bidi-wrap filenames, paths, urls, metadata

bidi.lua:
- Revert "Alias everything to Bidi.nowrap() when in LTR UI,
  as using LTR isolates seems uneeded when already LTR" (part
  of a628714f) which was a wrong assumption: we need proper
  wrappers for all things paths. Enhance some of these wrappers.
- Fix GetText RTL wrapping which was losing empty lines and
  trailing \n.

- Wrap all paths, directories, filenames in the code with
  these wrappers.
- Wrap all book metadata (title, authors...) with BD.auto(),
  as it helps fixing some edge cases (like open/close quotation
  marks which are not considered as bracket types by FriBiDi).
  (Needed some minor logic changes in CoverBrowser.)

- Tweak hyphenation menu text
- Update forgotten SortWidget for UI mirroring
- KoptConfig: update "justification" index for RTL re-ordering,
  following the recent addition of the page_gap_height option.

frontend/ui/widget/menu.lua

@@ -627,8 +627,7 @@ function Menu:init()
     if self.show_path then
         self.path_text = TextWidget:new{
             face = Font:getFace("xx_smallinfofont"),
-            text = self.path,
-            para_direction_rtl = false, -- force LTR
+            text = BD.directory(self.path),
             max_width = self.dimen.w - 2*Size.padding.small,
             truncate_left = true,
         }
@@ -1035,7 +1034,7 @@ function Menu:updateItems(select_number)
 
     self:updatePageInfo(select_number)
     if self.show_path then
-        self.path_text:setText(self.path)
+        self.path_text:setText(BD.directory(self.path))
     end
 
     UIManager:setDirty(self.show_parent, function()