metrics: specify telemetry hostname and instance name as prometheus labels

[cce]

Summary

This adds the telemetry hostname and instanceName to the labels passed to the MetricService, along with the other session label. They end up getting exported in Prometheus format as metric labels.

Test Plan

Existing tests should pass.

[codecov]

Codecov Report

Merging #4089 (e581ebb) into master (9237316) will decrease coverage by 0.06%.
The diff coverage is 35.00%.

@@            Coverage Diff             @@
##           master    #4089      +/-   ##
==========================================
- Coverage   54.55%   54.49%   -0.07%     
==========================================
  Files         391      391              
  Lines       48665    48669       +4     
==========================================
- Hits        26549    26521      -28     
- Misses      19890    19916      +26     
- Partials     2226     2232       +6     

Impacted Files	Coverage Δ
daemon/algod/server.go	4.87% <0.00%> (-0.13%)	⬇️
logging/log.go	41.26% <0.00%> (ø)
logging/telemetryConfig.go	81.81% <0.00%> (ø)
logging/telemetryhook.go	50.35% <0.00%> (ø)
network/requestTracker.go	71.12% <0.00%> (ø)
network/wsNetwork.go	64.98% <56.00%> (ø)
ledger/roundlru.go	90.56% <0.00%> (-5.67%)	⬇️
ledger/blockqueue.go	82.18% <0.00%> (-2.88%)	⬇️
network/wsPeer.go	65.47% <0.00%> (-2.20%)	⬇️
ledger/tracker.go	74.45% <0.00%> (-2.17%)	⬇️
... and 7 more

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[winder]

I don't know if I can approve this. Hostname was specifically removed prior to launch to limit any personally identifiable information. I think we have a proxy data point which includes a hash of the host name and data directory path.

Maybe Prometheus is fine since it's more deliberate to opt into that?

[cce]

The hostname feature you're describing must have been removed altogether — I only see getHostName which provides a GUID plus optional configurable "Name" which is what I'm interested in.