[RFC] Make default UI tapzones more generous (#6918)

* Top menu & bottom menu tapzones are now full-width, thanks to the now sane override system.
* A separate, extra tapzone was also created for each of them to provide a taller, but narrower tapzone extension (one that doesn't clash with the prev/next tapzones).
* The footer tapzone was made much taller.

frontend/apps/reader/modules/readerfooter.lua

@@ -632,9 +632,10 @@ function ReaderFooter:setupTouchZones()
             screen_zone = footer_screen_zone,
             handler = function(ges) return self:onTapFooter(ges) end,
             overrides = {
+                "readerconfigmenu_ext_tap",
+                "readerconfigmenu_tap",
                 "tap_forward",
                 "tap_backward",
-                "readerconfigmenu_tap",
             },
             -- (Low priority: tap on existing highlights
             -- or links have priority)