Rename Efl.Ui.Direction -> Efl.Ui.Layout_Orientation
This clarifies a bit the whole Orientation vs. Direction confusion, at the
expense of longer names (Image_Orientation vs. Layout_Orientation).
Also, the interfaces are now adjectives (Orientable) and the enums have long
Pretty big patch, but no functional changes.
Relates to T7863
Everything builds and passes tests.
Elementary_tests show same behavior, including the "inverted" widgets, which
are the only parts which received a bit of code changes.
Reviewers: zmike, bu5hm4n, cedric
Reviewed By: zmike
Differential Revision: https://phab.enlightenment.org/D8946