The commit adds a doc pointing out the internal actions needed
in order to make a release. It's based on the 2021A process, however,
it focuses more on the internal actions (within the IWG group).
This should help us not to forget anything when proposing a new
guideline plus it will help new contributors to get oriented quickly.
Change-Id: I89f5d3f20e95472573baba540dea9374441c4ad5