[addons] change maintainer

it's not me.
[addons] build for x86_64 only

I, as a maintainer of those addons, dont care for archs other than x86_64, so
they will not be built for i386/RPi/Cuboxi next bump and will disappear from
repositories. (I'll do a bump in next few weeks)

If you want some of those built for i386/arm - pelase feel free to take over
the maintainership (PRs welcome). I dont mind and I do not require any credits in
future if you decide to do so. All I want is: please keep x86_64 builds working.