[Tracking] Metrics

[Arkenan]

Metrics list:

• DB: Get/put/delete/encode/decode times for all "tables". This will be immediately completed with the issue Make DB modules to use KvSchema #1207.
• All main handlers:
  • Add metrics for request processing times #1209
  • Add metrics for gossip message processing times #1208
  • Add metrics for slot processing #1210
• Add metrics for state transition times. #1211
• Make a grafana node graph to represent the state of different blocks #1196
• Add cache metrics #663
• Fix the BEAM dashboard #1212
• Fix the ERTS memory allocators dashboard #1213
• Separate networking metrics from the rest #1214
• Merge prometheus_ex and telemetry_metrics_prometheus clients #903

Some ideas to evaluate:

• A simple card with whatever the libp2p port is doing at the moment. This might be useful for debugging, if the node hangs. However, if the card is not updated quickly enough, it's probably not going to be very useful.