Add channel status discovery

[ibmmqmet]

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What

Add a set of PCF operations for DISPLAY CHSTATUS and extracting the metrics from responses. Users wanting to see at least whether channels were running or not

How

New module for channel information; structured so similar QSTATUS or TPSTATUS could be added

Testing

Used a modified Prometheus monitor agent (to be released next) to see the stats

Issues

See #25