Metrics and JSON logging

[rarecrumb]

Is your feature request related to a problem? Please describe.
Observability would be nice to have, in the form of metrics. The option to enable JSON logging too.

Describe the solution you'd like
I'd love to see metrics implemented here:

• datadog: https://crates.io/crates/dogstatsd
• prometheus: https://crates.io/crates/metrics-prometheus

Key metrics could include:

• latency by RPC
• Errors by RPC
• Requests by RPC
• etc.

Describe alternatives you've considered
...

Additional context
Logging would also be nice to have in JSON format for search ability. Structured logs are nice.

[makemake-kbo]

[copy-pasting from discord]

it shouldnt be too hard. the macros used for logging are all in here so it would be a matter of adding a feature to support it https://github.com/rainshowerLabs/blutgang/blob/master/src/config/system.rs