Setup release, changelog, etc according to the guidelines

[Manuel Wiedenmann]

To comply with the adopted-ember-addons org guidelines we should setup the:

• release process #721
• changelog process #721

[Manuel Wiedenmann]

@knownasilya If you give me maintainer access I can do the setup for the release and changelog process

[Ilya Radchenko]

Should have write access now

[Manuel Wiedenmann]

Thanks. Will work on it over the weekend.