TouchMenu: tweak menu search (#9926)

- Cleanup search and animation codes, fix inconsistencies
  between animation/no-animation opening, and refreshes
  glitches on eInk.
- Show menu item on tap, with buttons to either open
  directly, or to walk there (removed earlier "Animation"
  checkbox, so the choice can be decided later).
- Move event handlers into ReaderMenu/FileManagerMenu.
- Avoid duplicated and confusing results from gestures
  and font-family submenus.

frontend/apps/reader/modules/readermenu.lua

@@ -538,6 +538,11 @@ function ReaderMenu:onSaveSettings()
     self.ui.doc_settings:saveSetting("readermenu_tab_index", self.last_tab_index)
 end
 
+function ReaderMenu:onMenuSearch()
+    self:onShowMenu()
+    self.menu_container[1]:onShowMenuSearch()
+end
+
 function ReaderMenu:registerToMainMenu(widget)
     table.insert(self.registered_widgets, widget)
 end