* move prometheus.register for unified storage metrics into metrics.go and do most of the plumbing to get it to work
* convert StorageApiMetrics to pointer and check for nil before using it
* rename type and variables to something more sensible
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Co-authored-by: Jean-Philippe Quéméner <jeanphilippe.quemener@grafana.com>
* adds extra debug logs and a new metric for poller query latency to help us better understand watch and index latency for write events
* adds trace span to the index for handling index write events
* adds metric for watch latency
* registers storage metrics when creating a new ResourceServer
* defines the latency (in milliseconds) as the diff between now and the RV. Still need to wait until PR for switching RV to millisecond timestamp is rolled out.
* should be micro seconds not milli
* for watch latency, use diff between now and resource version and convert to seconds
* fix typo
