* using fetchcontent to get zmq
* local copy of libzmq
* added guard for policy setting
* removed the need to export by using build interface
* removed zmq hint from cmk script
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Co-authored-by: Dhanya Thattil <dhanya.thattil@psi.ch>
Co-authored-by: froejdh_e <erik.frojdh@psi.ch>