Remove redis-server as required package on rpm/dep packages

[waldbauer-certat]

There are some redis drop-in replacements like keydb. So we might wanna change the required-dependency to optional.

https://build.opensuse.org/package/view_file/home:sebix:intelmq/intelmq/intelmq.spec?expand=1

[sebix]

Is it somewhere documented how to use other pipelines as replacement for redis? Including some information what works (well).

Changing the requirement from requires to recommends also means that for systems, which do not install recommended packages (e.g. minimal installations, including many docker image) do not end up with a working IntelMQ instance after installing the package.

I'd rather prefer, for the user experience's sake (the 98% of the users which use redis), that those, who use not redis, just disable redis themselves. It is rather easy:

systemctl disable redis-server

[waldbauer-certat]

As of now lets leave as it is, new ticket for more advanced configuration is available at #2222