Allow Metrics to be disabled

Problem Statement

Metrics may be expensive, and a user may choose to ignore the metrics that RediStack generates and prefer to use other metrics monitoring from hosts or Redis itself.

Proposed Solution

Extend RedisMetrics to have a enabled: Bool property, with a method that receives an auto-closure argument that does the metrics reporting only if enabled == true

By default metrics should still be reported. This can be re-evaluated later.