document picodata_version check on joining a cluster

Summary

• document picodata_version check on joining a cluster

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• Close #408 (closed)
• Cherry-pick to: none
• Staging:

https://docs.binary.picodata.io/picodata/at_inst_version_check/architecture/topology_management/#joining

https://docs.picodata.io/picodata/at_inst_version_check/architecture/system_tables/#\_pico_instance

https://docs.binary.picodata.io/picodata/at_inst_version_check/reference/audit_events/#join_instance