edje: Add support for map zoom to use other part center.

edje: Add support for map zoom to use other part center.

Summary:
Current:
In edc, zoom is supposed to happen from object center, there is no way to
change the center of the zoom.

Changes:
Adding support to change the center of zooming just like map rotation by using
other part's center.

@feature

Reviewers: cedric, zmike

Reviewed By: zmike

Subscribers: zmike, cedric, #reviewers, #committers

Tags: #efl

Differential Revision: https://phab.enlightenment.org/D9115