[dev] Branching thoughts

[Ralf Lang]

Hello,

I thought a little about how to transition without breaking everybody's 
stuff.
It's handy that the branch name "master" is not very popular these days 
anyway.

I will try to import all relevant developments from "master" into the 
"FRAMEWORK_6" branch of each repo.
FRAMEWORK_6 will contain all the fixes needed to eventually create 
tagged, php 8 to 8.2 compatible releases that end up on packagist. 
Including breaking changes as long as it's alpha.

@Rafael: This is a good opportunity to get the maintaina branches in 
sync and switch over to horde upstream for most stuff...