Do not consider the Evas_Vg API as BETA anymore

Do not consider the Evas_Vg API as BETA anymore

Summary:
It has been widely used for quite some time now.
Fixes T6889

Test Plan:
Manually built the evas-vg-simple.c and evas-vg-batman.c examples after
removing the manual define of EFL_BETA_API_SUPPORT and EFL_EO_API_SUPPORT
that they have at the top.

Reviewers: ajwillia.ms, zmike

Reviewed By: zmike

Subscribers: cedric, #committers

Tags: #efl

Maniphest Tasks: T6889

Differential Revision: https://phab.enlightenment.org/D6230

Change-Id: I6ade2d86773f14a6a48ccee7e9d3f9d3a3e6eba3