Add cli option to disable the default global zones

[RincewindsHat]

When setting up Icinga 2 agents, in most cases, the default global zones are not needed, but have to be removed manually or automatically whith tools outside of Icinga 2 from the configuration.

This seems like unnecessary work, since the node setup command does everything else.

This commit introduces a new option for the node setup command ("--no-default-global-zones") to exclude the default global zones.

[cla-bot]

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[RincewindsHat]

fixes #10023