focus: Change new API names related to focus auto scrolling.

focus: Change new API names related to focus auto scrolling.

elm_config_focus_auto_scroll_bring_in_enabled_get/set()
 ->
elm_config_focus_autoscroll_mode_get/set()

The main reason is that bring_in_enabled_get/set() APIs are too restricted
and thus not flexible. I got more requirements for the focus autoscrolling
such as none, wholely visible not just bring_in and show. So it is correct
to add mode_set/get() APIs for the focus auto scrolling.

Thanks god, we've found this before the release :)

@feature