Remove zabbix-agent, zabbix roles

docs/grafana.md

group_vars/all/common.yml

group_vars/mirrors.yml

group_vars/reproducible-builds.yml

host_vars/accounts.archlinux.org

host_vars/apollo.archlinux.org

host_vars/aur-dev.archlinux.org

host_vars/aur.archlinux.org

host_vars/bbs.archlinux.org

host_vars/bugs.archlinux.org

host_vars/dragon.archlinux.org

host_vars/gemini.archlinux.org

host_vars/gitlab.archlinux.org

host_vars/homedir.archlinux.org

host_vars/luna.archlinux.org/misc

host_vars/matrix.archlinux.org

host_vars/mirror.pkgbuild.com

host_vars/phrik.archlinux.org/misc

host_vars/quassel.archlinux.org

host_vars/reproducible.archlinux.org