[Satellite 6] How to copy foreman-proxy user public ssh key to many client systems for Remote Execution

Issue

Setting up Satellite's Remote Execution feature requires copying the foreman-proxy user's public ssh key to the service accounts of all client systems. This can be copied to systems individually using # ssh-copy-id -i ~foreman-proxy/.ssh/id_rsa_foreman_proxy.pub service_account@target.system where service_account is the remote_execution_ssh_user as defined on the Satellite.

However this is not feasible to implement when there are many (dozens, hundreds, thousands) of hosts that need to have the ssh keys copied -- how can this operation be performed on larger environments?