[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.

plugins/docsettingtweak.koplugin/main.lua

@@ -1,3 +1,4 @@
+local BD = require("ui/bidi")
 local DataStorage = require("datastorage")
 local FFIUtil = require("ffi/util")
 local InputDialog = require("ui/widget/inputdialog")
@@ -48,7 +49,7 @@ function DocSettingTweak:editDirectoryDefaults()
     directory_defaults_file:close()
     local config_editor
     config_editor = InputDialog:new{
-        title = T(_("Directory Defaults: %1"),directory_defaults_path),
+        title = T(_("Directory Defaults: %1"), BD.filepath(directory_defaults_path)),
         input = defaults,
         input_type = "string",
         para_direction_rtl = false, -- force LTR