Suggestion: Changes to release process, release from branch

Hi Andreas,

> * No changes to the procedure during soft freeze and freeze, no changes to basic
>  timetable
>
> * With the hard freeze two weeks before nominal/last possible release date, 
>  the release branch is made, and the master branch is re-opened for development.

Would it make sense to make it ~4 weeks to give distros time to start testing and give
feedback? It also leaves more time for important bugfixes. Given GLIBC is pretty stable
most of the time (at least for the main targets), we could branch earlier.

Any fixes would first go into master for CI testing and then selected in the weekly
meeting for an automated cherrypick into the release branch.

Cheers,
Wilco