Update manifest file format for engine script
Supported by following commit:
commit 33f2570d15a1feae16d2b5b83f73ff93fd951843 Author: Steel Wheels Project <wheel@tcn.zaq.ne.jp> Date: Sat Mar 16 15:59:25 2019 +0900 AmberComponent: Update manifest file format to add engine section
Update manifest file format for engine script. Append "engine" section to set JavaScript file to implement engine.