Consider adding prefixes to refinery logs

[cartermp]

From a customer:

Note on sending Refinery's own logs to Honeycomb...
They wind up not getting a meta.signal_type attribute...
Also no service.name or app attribute.
We had to use the hostname to find them...

Example log line:

api_host: <host>
dataset: <datasetname>
environment: prod
error: <error message>
hostname: refinery-asfljangonafs-asfkabjsfjnasf
level: error
msg: error when sending event
process_uptime_seconds: 19
refinery_version: 2.7.1
roundtrip_usec: 63341
status_code: 0
trace.span_id: 76d4f990ca0813f8
averageResponseSeconds: 0
failureRate: 0
failureRateNew: 0
maxResponseSeconds: 0
p95ResponseSeconds: 0
successRate: 100
traceDurationSeconds: 0

I think there's some that shouldn't get prefixed (e.g., trace.span_id since it's already prefixed). But given that we encourage meaningful prefixes for fields generally, and in an E&S + OTel world people will be using certain fields to find and filter things in an environment, this makes sense to me.