Convenience methods to connect Health Metrics to Small Peer Info

[bplattenburg]

Add a convenience function to attach Health Metrics as a part of Small Peer Info metadata so that customers can use a single health collection instead of needing a separate heartbeat collection.

This should support:

• Getting the existing metadata, then adding / updating a list of health metrics under the key healthMetrics
• Takes in a list of HealthMetricProviders and an interval (see below)
• Configuring a regular interval (in seconds) at which to update this data onto Small Peer Info, defaulting to every 5 mins. Enforce a minimum interval of 30 seconds.