evas_vg_json: Add image embedded example

evas_vg_json: Add image embedded example

Summary:
add example code and json resource.

plus)
Add ECTOR_BACKEND="default" Environment variable
because cairo backend is not supported.

Depends on
D9218 Ector.Renderer : Implement Ector.Renderer.(Software).Image class
D9219 Efl.Canvas.Vg : Implement Efl.Canvas.Vg.Image class
D9220 vg_common_json : Support image data of node

Test Plan:
cd .src/examples/evas/
gcc -o evas_vg_json evas-vg-json.c `pkg-config --libs --cflags evas ecore ecore-evas eina ector eo efl`
./evas_vg_json

Reviewers: Hermet, kimcinoo, smohanty

Subscribers: bu5hm4n, cedric, #reviewers, #committers

Tags: #efl

Differential Revision: https://phab.enlightenment.org/D9351