docs: How to set ms_bind_port_min?

[amd-jhorng]

Please describe the question or issue you're facing with "cluster - MicroCeph documentation".

We have service running in the 68xx port range. I was able to to move the osd port by using the
ms_bind_port_min = 6900 but the setting gets reset if the node was rebooted. Is there a way to permanently set this globally

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Reported from: https://canonical-microceph.readthedocs-hosted.com/en/squid-stable/reference/commands/cluster/