feat: actually record metrics

[tdakkota]

ch.Client currently takes an option to set an OpenTelemetry MeterProvider, however it does not create any metrics.

Useful metrics ch.Client may provide:

• Total number of written/read rows, packets and bytes, including compressed and uncompressed
• Histogram of query latency

Useful metrics chpool may provide:

• A gauge of idle/active connections
• A counter of created/destroyed connections
• Acquire time latency

Refs:

• semconv for DB metrics and attributes
• database/sql.DBStats as reference for pool metrics
• (*puddle.Pool).Stat as reference for pool metrics