efl_gesture: rename Efl.Gesture.Events to Efl.Canvas.Gesture_Events

efl_gesture: rename Efl.Gesture.Events to Efl.Canvas.Gesture_Events

Summary:
Since the current Efl.Gesture.Events has canvas gesture events only,
Efl.Gesture.Events should be renamed to Efl.Canvas.Gesture_Events.

If other types of gesture events are newlly required later, which are
not based on canvas, then class Efl.XXX.Gesture_Events is required to
be introduced.

Reviewers: CHAN, segfaultxavi, bu5hm4n, zmike

Reviewed By: segfaultxavi

Subscribers: cedric, #reviewers, #committers

Tags: #efl

Differential Revision: https://phab.enlightenment.org/D11073