README: Add Communication section with Forum information (#8732)
* README: Add Communication section with Forum information
* Changelog fragment isn't needed for README change.
* Distinguish between Get Help and the community-general tag.
* Update links.
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Co-authored-by: Felix Fontein <felix@fontein.de>
(cherry picked from commit 4cb4c608d0)
Co-authored-by: Andrew Klychkov <aklychko@redhat.com>