Expose Cassandra related system properties in a virtual table

Allow viewing Cassandra related system properties.

Viewing yaml config settings, as implemented by SettingsTable in CASSANDRA-14573, is not enough for certain third-party tool use-cases. There are a number of system properties that can be defined that contribute to the configuration set that Cassandra runs on.

An example of such a use-case is described in CASSANDRA-15339. JMX ports need to be discovered, especially in 4.0 where multiple nodes can run on one ipaddress. Unlike the native port that is through gossip discoverable, the jmx port is not. The jmx port is also not available via the SettingsTable. With this patch and SystemPropertiesTable it becomes possible to first discover all the native ports in the cluster and against each then discover each node's jmx port.