Stop defining EFL_BETA_API_SUPPORT in Efl_Core.h and Efl_Ui.h

Stop defining EFL_BETA_API_SUPPORT in Efl_Core.h and Efl_Ui.h

Summary:
Including these headers does no longer mean that you want to use BETA API.
More and more methods in these libs will come out of BETA and they will
be usable without requiring EFL_BETA_API_SUPPORT to be defined by the app.

This concludes this patchset. Now apps can chose to define EFL_BETA_API_SUPPORT
or not, and they will have access to the requested API subset, but both options
are available.

Depends on D7951
Fixes T7692

Reviewers: zmike, bu5hm4n, cedric

Subscribers: #reviewers, #committers

Tags: #efl

Maniphest Tasks: T7692

Differential Revision: https://phab.enlightenment.org/D7952