Add ABCI method timing histogram metric

[aWN4Y25pa2EK]

This PR introduces a new histogram metric, abci_connection_method_timing_seconds, to measure the timings for each of the ABCI methods. This metric will help in tracking and analysing the performance of various ABCI methods by providing detailed timing information. The metric includes labels for method and type to allow for granular analysis of the data.

Changes Introduced

• New Metric: The abci_connection_method_timing_seconds histogram metric is added to capture the duration of ABCI method calls.
• Metrics Struct Update: The Metrics struct is updated to include the new histogram metric.
• Prometheus Metrics Initialization: The PrometheusMetrics function is updated to initialize the new histogram metric with appropriate labels.
• No-Op Metrics Update: The NopMetrics function is updated to include a no-op version of the new histogram metric.

Files to Review

metrics.go: This file contains the primary changes for adding the new metric. It includes updates to the Metrics struct, the PrometheusMetrics function, and the NopMetrics function.

Importance

Tracking the performance of ABCI methods is crucial for understanding and optimizing the behavior of the system. By adding this metric, we provide operators and developers with a tool to gain insights into the timing of different ABCI method executions, which can help in identifying bottlenecks and improving the overall efficiency of the system.

[rach-id]

I see the ABCIMethodTimingSeconds added, but I don't see it being used anywhere. How does this new metric capture the values?